Monday, September 26th 2011
Kathedrale balloon, i.e., not how I am traveling this semester
This is my first semester as an academic where I have a significant travel component. I realized that some of you might want to know where and when I’m traveling or speaking, in case you live in the area and want to hear me speak or organize a tweetup. So here is my tentative schedule for the fall. I should be giving one more talk this fall, but it is not on here because we haven’t scheduled it yet.
September
September 22nd and 23rd, Purdue Conference for Pre-Tenure Women. I didn’t speak at this, but was a humble attendee who learned a whole lot. I will write a post on this some time next week.
September 28th, the Ig Nobel Awards. 7:30pm, Sanders Theatre, Harvard University. I’ll be giving one of the 24/7 talks, on the topic of vaginal pH. That’s right, the same topic as my douching post last month, and yes, that blog post is what scored me the invite. The Ig Nobels are already sold out, but I am around Friday the 29th as well.
October
October 12th, Teaching with Technology Brown Bag Series. 12pm, 23 Illini Hall, University of Illinois. “Sneak a little science into their day: Blogs in teaching.” I’ll be talking about the various ways I use blogs in education: for private journals, to present findings to a broader audience, as readings in lower-level courses, and to engage students with an interested laypublic (that would be you all).
October 26th and 27th, University of Tennessee, Knoxville Anthro Visiting Lecture Series, Anthropology in the Public Sphere: (Re)Defining Research and Practice for the 21st Century. I am very excited to have been invited to speak at this lecture series. You can find me on the 26th at 10:10am, UC Auditorium speaking on “Connecting women and their bodies: broader impacts that actually have impact,” and on the 27th at 3:40pm in MM 63 speaking on “Why you should be reading scienceblogs, and why I tell the internet all about the ladybusiness.” I believe the first lecture is more of an upper-level course and the second lecture is for undergrads, but I intend to speak in a way accessible to anyone. Members of the public are explicitly encouraged to attend.
November
November 2nd, Sociology of Health and Illness Seminar. 3:30pm, 313 Davenport Hall, University of Illinois. “Women’s reproductive health” (better title TBA). This will be an overview of my research and how it intersects with issues of health and illness.
November 10th or thereabouts. Harvard University. I will be giving two talks, one more on gender, bias and science, and another that is a more traditional bio anthro research talk that week. Details TBA.
Friday, September 16th 2011
My daughter wearing a towel the way Mommy does.
This morning was a bit rough. “Where’s Daddy?” asked my daughter as she climbed into bed before dawn to snuggle. “It was Daddy’s turn to go to work early,” I explained. It used to be that I was the parent she turned to for everything. But the last few weeks, with preschool and a new system of pickups and drop-offs, four days a week I walk to work at six, before she usually rises. This is so that I may pick her up at 3:45 but still work a full day.
And now Daddy is the one with the morning ritual, the one who helps her pick out her clothes and make her bed. They call me at work most mornings to say a quick hello so the kiddo can tell me any dreams she had and what she is having for breakfast. Then Daddy brings her to school, helps her get into her indoor shoes and put away her lunch, helps her choose her activities during free time, and heads into work.
So we snuggle some more. I ask, “What do you want for breakfast?” She names the local restaurant we go to on the weekends. “It’s a weekday, honey, you have school soon.” She said, more forcefully this time, that she wants to go out to breakfast. Hoping to win back her love, I say, “How about I make you French toast this morning?”
“With the sprinkles.” She is referring to the dusting of powdered sugar that comes with it at the restaurant.
“How about just syrup? You don’t need both.”
“With sprinkles!”
I sigh. This is our one morning together during the week. I want it to be a good one. “Okay,” I say.
I forget to make the beds, almost forget to get her teeth brushed, have to avert several outfit disasters, and forget to call Daddy. Thankfully Daddy calls us, and we chat for a few minutes while the kiddo eats her French toast and glass of warm milk. Then I barely get her to school on time due to a power play about who gets to buckle her up, don’t know how to help her with choices for free time, and only barely manage to get her sneakers off.
Clearly, Daddy has the morning routine down.
* * *
Parenting, caring for offspring, and the work-life balance are issues usually relegated to women. There are many men who take care of their kids, and increasingly men in the US and other countries who invest at least as much or more than mothers, but these men are considered both outliers and, often, heroes. The biological imperative to parent, and the reproductive burden, is supposed to fall squarely on women, and it is only our wonderful cultural sensitivity broadening that perspective more recently.
What if there were a biological imperative to be a loving father? Or what if being a father was good for you?
Over the last decade or so, biological anthropologists have studied the biology of mating, partnering and fatherhood of men (e.g., Burnham et al. 2003; Gettler et al. 2011b; Gray et al. 2002; Gray et al. 2004). As it turns out, these different periods of men’s lives have distinct hormonal milieus, just like the reproductive states of women like fecund, pregnant, breastfeeding and grandmothering. When men are seeking mating opportunities, testosterone is high to support mating behavior, muscle anabolism, and the other secondary sexual characteristics that allow a man to display his good genes. When men are partnered in long-term relationships or become parents, testosterone often declines. And the more a man spends with his offspring, the greater the decline.
What I have noticed missing from the stories about the most recent paper on testosterone and fatherhood is the fact that, from a survival perspective, testosterone is bad for you! Look at lizards who, injected with testosterone, do pushups to attract mates until they die from the effort. Look at the health complications of men who inject themselves with steroids. Testosterone does at least two awful things to your body: it reduces your immunocompetence and it may increase your risk of male reproductive cancers (Muehlenbein and Bribiescas 2005). Further, some have studied the impact of both marriage and having children on longevity. Men almost always benefit from both (click here for a post that addresses this, albeit indirectly, at my old digs — look in particular at the second graph, from Jasienska et al 2006). The trade-off when seeking mating opportunities is that at least you’re getting the good out of testosterone: the support of the kinds of traits that may help you find a mate, despite a reduction in somatic allocation that can improve survivorship (Bribiescas 2001).
Model of the trade-off between reproductive effort and survivability in males (Muehlenbein and Bribiescas 2005).
But when you aren’t looking for a mate, or when those behaviors could actually be detrimental to your reproductive success, there is little reason to continue to invest energy in having high testosterone. Testosterone is one of those hormones that varies hugely (Ellison et al. 2002), because such a tiny amount is needed to support reproduction and libido yet it affects, and is affected by, behavior. Most men have loads more testosterone on a daily basis than they will ever need to make a baby the few times they may want to.
The most recent paper to come out about testosterone and fatherhood is the first to examine this relationship longitudinally, and this dataset confirms the cross-sectional data that came before it (Gettler et al. 2011a). I first learned about these data from Dr. Peter Gray, an Associate Professor of Anthropology at the University of Nevada, Las Vegas. He is one of the pioneers in the field, answering questions about the state of fatherhood from an endocrinological perspective both within and between human populations all over the world.
Because I know Peter (full disclosure: we took one class together when I was an undergraduate, and he a grad student, at Harvard), I asked him if he would answer a few questions for me about the state of the field, and what it means for men that testosterone can vary due to parenting behavior. He was kind enough to do so despite being in the field right now. His answers illuminate the importance of the current results and put them into a broader context, and also demonstrate his generousness as a scholar and dad.
* * *
What is the history of the study of this field?
In the 1980s and 1990s, a considerable amount of work on nonhuman animals, particularly North American birds, helped generate a sense of the social side of testosterone. Put simply, work on various animals illustrated the ways in which male testosterone levels shifted in response to male-male competition, courtship, longer-term bonding, and parental care. The first human testosterone and male family life studies were based on large U.S. military samples, and showed that married men had lower testosterone levels and testosterone levels increased slightly around the time of divorce. However, it was only in 2000 — a new millenium, appropriately enough — that human studies were published connecting the wider evolutionary and comparative literature. The first testosterone and fatherhood study, showing that dads shortly after birth had lower testosterone in a highly-invested Canadian sample, was published in 2000 by Anne Storey and colleagues. Since that time, more and more scholars, in more and more study populations (from Boston to Beijing, the Hadza to Jamaica), have found through cross-sectional designs that family men — men involved in long-term committed relationships and paternal care — tend to have lower testosterone levels.
Were there ever any roadblocks to you pursuing research into testosterone and mating patterns or parenting behavior?
There hasn’t been a single roadblock, but there have been recurring issues that arise in these kinds of studies. Recruiting men can be easier or more difficult, depending on the study circumstances. It can be challenging to get busy fathers of young children to go out of their way to participate. For the Jamaican fatherhood study, for example, we asked fathers to report to a testing facility with their partner and youngest child for procedures, making recruitment a significant effort. Another issue is how involved these studies are: the easier for participants, the more likely participation. That’s especially true, I think, of biological sampling. By relying on minimally invasive saliva sample (rather than blood draws) for most studies, that has probably had a huge positive impact on recruitment and ease of conducting studies. Last, I might add that my own life history realities — as a father of two young children — has posed its own juggling act, where I try to combine meaningful scholarly work with engaged family life.
What is one of the coolest findings to come out of your research? The research in this field more broadly?
I love how integrated this set of studies on human testosterone and family life is with the wider evolutionary, comparative, and endocrine work. There’s no setting humans part from nature here. We’re folded fully into its fabric, and that’s been reflected in the theoretical and conceptual foundations underlying hypothesis generation and interpretations. I also like the intersections with wider social and health concerns. When I was a postdoc between 2003-2005 working in Shally Bhasin’s Clinical Endocrine Lab, juicing baseball players were making headlines, and that folded seamlessly into the wider understanding of what androgens can do, and their respective costs and benefits. So too do discussions of male aging and efforts to quantify the risks and benefits of testosterone therapy in aging men. All of these elements — from the social side of testosterone to the health and home run angles — can be integrated within wider evolutionary and endocrine principles.
What’s something we know now because of this study (Gettler et al 2011a) that we didn’t know before? What is its main contribution?
The main contribution is the rigorous study design. In particular, this study has a large sample. It is a community-based sample from the Philippines. And, most importantly, it employs a longitudinal design. That longitudinal element demonstrates causality. While the growing pile of testosterone and family life studies were based on cross-sectional designs, one could ask whether lower testosterone men became dads or whether fatherhood caused testosterone decreases. Gettler and colleagues’ study shows convincingly that becoming a father decreases men’s testosterone. It also showed that men with higher testosterone were more lkely to initially marry and become fathers, after taking a testosterone plunge, a finding that itself is of interest and calls for more work.
If there was one thing you wanted people to understand about testosterone and fatherhood, what would it be?
There are impacts of fatherhood on men, from how they feel to their health to their physiology. This finding of testosterone declining with fatherhood makes sense in light of comparative, endocrine, and overall evolutionary considerations, not to mention the kind of day-to-day differences fathers might recount in the ways their lives are structured compared to their ‘single’ days. Fatherhood bears its stamp upon men’s testosterone in perhaps, then, some unsurprising ways.
What is a current project you are working on?
I’m involved in a collaborative fatherhood project in Jamaica, working with Maureen Samms-Vaughan, a Jamaican pediatrician. This is a new questionnaire-based national cohort study. While she and others on the project are primarily interested in mothers and child development, I’m working with her on the fatherhood arm of the study. This entails fathers during the day or two post-birth answering questions about paternal attitudes, partner relationships, sexuality, health, and more. Men’s responses can be linked with maternal and child outcomes, and some of men’s responses should be of interest in themselves. As an example, one issue concerns son vs. daughter preference, a topic that is often bracketed by male preferences among some in China and India, whereas there may be leanings toward a general daughter preference in the Caribbean, but perhaps that will be attenuated among fathers. About 1000 men have responded so far, with more yet before the study wraps up soon. This should be a really promising and exciting study, with an unusually large sample and with potential for longitudinal work as well.
I’m also working with Justin Garcia, a postdoc at the Kinsey Institute, on an integrative, evolutionary-oriented book on human sexuality. That’s plugging along well, with the manuscript’s due date the end of this year, and its gestation so far on target.
Where can people go to read more on this topic?
I would recommend the Gettler et al. PNAS article at the starting line. For general background on behavioral endocrinology, Randy Nelson’s textbook An Introduction to Behavioral Endocrinology has just been updated (a revised 2011 edition) and provides an excellent survey of the field. For work that provides general conceptual background, excellent comparative data points, and some of the most empirically-rich human findings, Peter Ellison and I coedited Endocrinology of Social Relationships, published in 2009 by Harvard University Press. And for an integrative account of human fatherhood, featuring an evolutionary perspective, comparative work, cross-cultural research, and arguably unique syntheses of topics such as male work/family/social relationships trade-offs, health and fatherhood, and sexuality and fatherhood, Kermyt Anderson and I wrote Fatherhood: Evolution and Human Paternal Behavior, published in 2010 by Harvard University Press.
* * *
Thanks to Dr. Peter Gray for his comments. What are your questions? What implications does this research have for your reproductive decisions or how you run your family life? Me, I’m going to try to not feel so guilty about my early mornings at work and our 50/50 co-parenting. My husband has chosen to be an involved father, and the love and patience he gains from the experience, not to mention the drop in testosterone, can only be a good thing for his survivorship, which will make it possible for him to be an involved grandfather.
References
Bribiescas RG. 2001. Reproductive ecology and life history of the human male. American Journal of Physical Anthropology 116(S33):148-176.
Burnham TC, Chapman JF, Gray PB, McIntyre MH, Lipson SF, and Ellison PT. 2003. Men in committed, romantic relationships have lower testosterone. Hormones and Behavior 44(2):119-122.
Ellison PT, Bribiescas RG, Bentley GR, Campbell BC, Lipson SF, Panter-Brick C, and Hill K. 2002. Population variation in age-related decline in male salivary testosterone. Human Reproduction 17(12):3251.
Gettler LT, McDade TW, Feranil AB, and Kuzawa CW. 2011a. Longitudinal evidence that fatherhood decreases testosterone in human males. Proceedings of the National Academy of Sciences.
Gettler LT, Mcdade TW, and Kuzawa CW. 2011b. Cortisol and testosterone in Filipino young adult men: Evidence for co regulation of both hormones by fatherhood and relationship status. American Journal of Human Biology 23(5):609-620.
Gray P, Kahlenberg S, Barrett E, Lipson S, and Ellison P. 2002. Marriage and fatherhood are associated with lower testosterone in males. Evolution and Human Behavior 23(3):193-201.
Gray PB, Chapman JF, Burnham TC, McIntyre MH, Lipson SF, and Ellison PT. 2004. Human male pair bonding and testosterone. Human Nature-an Interdisciplinary Biosocial Perspective 15(2):119-131.
Muehlenbein MP, and Bribiescas RG. 2005. Testosterone mediated immune functions and male life histories. American Journal of Human Biology 17(5):527-558.
Friday, September 9th 2011
I love science, and I love the scientific method. I think that the scientific method is one of the most useful ways of knowing out there. I have devoted my life not only to the study of the science of human evolution and female reproductive physiology, but to increasing science appreciation and literacy in the general public.
So why am I always criticizing it?
Two reasons. First, the process of science can be biased by who performs it.
Second, the results and implications of scientific research can be biased by who tells it.
To demonstrate this, I’m going to tell you a little story about a menstruating nurse.
* * *
Dr. Bela Schick, a doctor in the 1920s, was a very popular doctor and received flowers from his patients all the time. One day he received one of his usual bouquets from a patient. The way the story goes, he asked one of his nurses to put the bouquet in some water. The nurse politely declined. Dr. Schick asked the nurse again, and again she refused to handle the flowers. When Dr. Schick questioned his nurse why she would not put the flowers in water, she explained that she had her period. When he asked why that mattered, she confessed that when she menstruated, she made flowers wilt at her touch.
So, rather than consider the possibility that the nurse was offended that her skills and expertise were being put to use to put someone else’s flowers in water, Dr. Schick decided to run a test. Gently place flowers in water on the one hand… and have a menstruating woman roughly handle another bunch in order to really get her dirty hands on them:
An image of the menotoxin flowers experiment. One vase of flowers is wilted while the other is not.
The flowers that were not handled thrived, while the flowers that were handled by a menstruating woman wilted.
This was the beginning of the study of the menstrual toxin, or menotoxin, a substance secreted in the sweat of menstruating women.
* * *
This story begins far before Dr. Bela Schick and his menstruating nurse. Because the kind of bias that produces a doctor who can believe that menstrual toxins exist, and launch a field of study on them based on some wilted flowers (if the story really did happen the way he tells it), did not come from one man alone. The cultural conditioning that has produced the idea that women are dirty, particularly during menses, is quite old. The Old Testament of the Bible claims that women are unclean when they menstruate, and menstrual huts exist in some cultures to separate out menstruating women from the rest of their group.
But some mark the beginning of our misunderstandings of female physiology in European-derived cultures with one book in particular written in the thirteenth century – De Secretis Mulierum, The Secrets of Women. This book was written by a man who claimed to be the monk Albertus Magnus, but was most likely an impersonator (which is why most call the author of De Secretis Mulierum pseudo-Albertus Magnus, or pseudo-Albert).
So here are some winning quotes from this book, which was considered a premier text for several centuries, even though it is likely pseudo-Albertus Magnus never treated women and based much of his work on having dissected a female pig:
“Woman is not human, but a monster.”
Menstruating women give off harmful fumes that will “poison the eyes of children lying in their cradles by a glance.”
Children conceived by menstruating women “tend to have epilepsy and leprosy because menstrual matter is extremely venemous [sic].”
De Secretis Mulierum went through at least eighty editions over several centuries (Rodnite Lemay 1992). While it was not a strictly medical text, it is clear that it was both popular and influential. Do doctors refer to De Secretis Mulierum today? Of course not. But this book, to me, represents a broader cultural understanding that menstruation is dirty, that women are powerful, mysterious, dangerous, and sub-human.
* * *
This figure is from a study that did not support the existence of the menotoxin, as there were not significant differences in phytotoxicity in the blood of menstruating and non-menstruating women, under what these authors argued were more rigorous experimental standards (Freeman et al. 1934). Only paper I could find with repeatable methods and data, and interestingly, the only one that rejects the menotoxin hypothesis.
So back to those menotoxins. Dr. Schick decided there was something nasty in the sweat of menstruating women. Others took up the cause. Soon, people were injecting menstrual blood into rodents, and those rodents were dying (Pickles 1979). Others were growing plants in venous blood from menstruating women to determine phytotoxicity; the sooner the plants died, the higher the quantity of menotoxin assumed in the sample.
What’s worse, the presence of the menotoxin in the female body began to expand beyond menstruation. Any woman who was post-menarcheal and pre-menopausal could be found to have the menotoxin in her system. She could not escape it: some reported that the menotoxin could be found in a woman’s menstrual blood, but also venous blood, sweat, and breastmilk. One case study reports that a mother gave her child asthma because she was menotoxic during pregnancy (Perlstein and Matheson 1936), and several contended that colic was caused by menotoxin in breastmilk (Ashley-Montagu 1940; Perlstein and Matheson 1936).
Not only did the idea of the menotoxin become a ubiquitous menace around any reproductively-aged woman, it began to explain pathology. So the menotoxin, which first was an explanation for the presence of menstruation in women, became a way of diagnosing women as ill… and again, since now all reproductively-aged women could secrete it from any bodily fluid at any time, the state of being female essentially made one pathological.
Soon the idea that the menotoxin indicated specific illnesses began to take hold.
“Dr. Schick and I discussed the possibility that the adult female diabetic out of control, the depressed adult female psychotic, and the adult female in the premenstrual phase secreted some common substance in their sweat.” (Reid 1974)
Here, you see premenstrual women compared directly with two pathological conditions: diabetes and psychosis. And all of these relationships, between menstruation and colic, asthma, wilted flowers, are largely observation, case reports, or poorly controlled experiments. When studies do not support the idea of the menotoxin, as with Freeman et al (1934) and two studies cited by Ashley-Montagu (1940) that were not in English, each get dismissed as outliers (even though in Labhardt’s case from Ashley-Montagu, the sweat of men was often as toxic as that of menstruating women).
And this is where I bring it back to my first two points about bias, that science can be biased by the cultural conditioning of those who perform it, and those who tell it. The people who studied the menotoxin really, really wanted to believe in it, to the point that they would ignore negative results and overstate the power of their anecdotes and case studies. The study of the menotoxin spans at least sixty years, maybe ninety depending on which references you consider legitimate, debated in Lancet letters to the editor, and published in several medical journals.
I wish I could say that the menotoxin was dead. But several contemporary hypotheses about the evolution of menstruation still in some way reflect the thinking that menstruation, if not women, is dirty and serves the purpose of expelling toxicity. Clarke (1994) proposed menstruation as a mechanism to expel unwanted embryos. Margie Profet (1993) argued that menstruation helped to expel sperm-borne pathogens, which made men the dirty party. This is why it’s important to recognize that many ideas that seem intuitive to us at first derive from cultural conditioning and bias. (My favorite book on the topic is Emily Martin’s The Woman in the Body (1980).)
Thankfully, the most accepted idea is that menstruation did not evolve at all, but is a byproduct of the evolution of terminal differentiation of endometrial cells (Finn 1996; Finn 1998). That is, endometrial cells must proliferate and then differentiate, and once they differentiate, they have an expiration date. Ovulation and endometrial receptivity are fairly tightly timed, to the point that the vast majority of implantations occur within a three-day window (Wilcox et al. 1999). So it’s not that menstruation expels dangerous menotoxins, but rather that menstruation happens because the endometrium needs to start over, and humans in particular have thick enough endometria that we can’t just resorb all that blood and tissue.
It’s time to dump the idea that menstruation is dirty. It’s blood and tissue that you ended up not using to feed a baby, and that’s all.
*I want to credit one of my favorite courses from college for much of the content related to pseudo-Albertus Magnus: Women’s Studies 106a, Bodies and Boundaries, taught by Prof. Katherine Park at Harvard University. I have no idea if it’s still taught (*cough* it’s been ten years *cough*), but if you are a student there, you are missing out if you don’t take a class with her.
**If you are a historian of science and would like to talk over this material with me, let me know! It would make for a great paper.
References
Ashley-Montagu M. 1940. Physiology and the Origins of the Menstrual Prohibitions. The Quarterly Review of Biology 15(2):211-220.
Clarke J (1994). The meaning of menstruation in the elimination of abnormal embryos. Human reproduction (Oxford, England), 9 (7), 1204-7 PMID: 7848450
Finn CA (1996). Why do women menstruate? Historical and evolutionary review. European journal of obstetrics, gynecology, and reproductive biology, 70 (1), 3-8 PMID: 9031909
Finn CA (1998). Menstruation: a nonadaptive consequence of uterine evolution. The Quarterly review of biology, 73 (2), 163-73 PMID: 9618925
Freeman W, Looney JM, and Small RR. 1934. Studies on the phytotoxic index II. Menstrual toxin (“menotoxin”). Journal of Pharmacology and Experimental Therapeutics 52(2):179-183.
Martin E. 1980. The woman in the body. Beacon Press, Boston.
Perlstein M, and Matheson A. 1936. Allergy Due to Menotoxin of Pregnancy. Archives of Pediatrics and Adolescent Medicine 52(2):303.
Pickles VR (1979). Prostaglandins and dysmenorrhea: Historical survey. Acta Obstet Gynecol Scand Suppl 87:7-12.
Profet M (1993). Menstruation as a defense against pathogens transported by sperm. The Quarterly review of biology, 68 (3), 335-86 PMID: 8210311
Reid HE (1974). Letter: The brass-ring sign. Lancet, 1 (7864) PMID: 4133673
Rodnite Lemay H. 1992. Womens Secrets: A Translation of Pseudo-Albertus Magnus’ de Secretis Mulierum with Commentaries: State University of New York Press.
Wilcox AJ, Baird DD, & Weinberg CR (1999). Time of implantation of the conceptus and loss of pregnancy. The New England journal of medicine, 340 (23), 1796-9 PMID: 10362823
