A study following 600 men for over 5 years demonstrated that fatherhood and being involved in the raising of a child lowers testosterone levels (Gettler, L. et al., 2011). While the study is very interesting it raises many questions for me that are left unanswered.
It is known that testosterone levels decrease over a man’s lifetime, but it was shown in this study that the men that fathered children and had a relationship with the child had lower testosterone levels than their child-less counterparts. It was also found that those that spent three hours or more per day involved with the child had even lower testosterone levels. This leads me to question if a possible feedback loop is involved. The more involved the men are, the lower the testosterone levels indicating a possible positive feedback loop.
Having lower testosterone levels was linked in the study to possibly being a “better” father. It could be suggested that these lower testosterone levels allow the men to be more driven to tend to their children and less driven to seek out another mate. Men do not have the same physiological effects in becoming a parent that women do. Women have the physiological experiences of carrying the child, giving birth and suckling the young, all of which allow the woman to become emotionally connected with the child. Possibly this lowering of testosterone levels allows the men to become emotionally connected with the child much as the physiological effects that women experience do.
Women “nest” after having a child by securing a healthy and sheltered home and providing for their child. Does the drop in testosterone levels allow men to have a similar urge to “nest”? Our young are not self-sufficient and require many years of care; many parents would even argue that the work required to raise a successful child never ends. This child care is generally socially and culturally considered the responsibility of the women, but does this drop in testosterone levels suggest that men are physiologically wired to be involved in their children’s lives and help women in the child care?
This study brings up another question: is the most involved father, the one with the lowest levels of testosterone, “less of man” or “more of a man”?
The question posing a possible link between decreasing testosterone levels and being "physiologically wired to be involved" in raising a child was really interesting to me. It stands to reason that if a woman produces specific hormones like increased levels of estrogen during pregnancy then the decreased testosterone levels men experience must be somehow linked to the long-term relationship to a child. It was interesting to consider the decreased testosterone as a physiological replacement experience for men when women have the physiological features of nursing, etc. you mentioned.
ReplyDeleteAt first, I was a little confused about how the more involvement a man has with his child, the more his testosterone levels will drop was a positive feedback loop. But taking a second look at the article made me think the drop has to be the result of a positive feedback loop with the increasing original stimulus of decreasing testosterone. The observed three hours or more of direction contact or stimulation suggest the feedback loop increases on itself when it would dramatically decrease if it was a negative feedback loop.
Your question of the lowest levels of testosterone resulting in "less or more" of a man made me think again of the hormones women experience during pregnancy. With the increasing estrogen women experience does it mimic the "less or more" possibility of manliness when women are considered more womanly after giving birth in our society? The physical characteristics that change into a more "womanly" look such as the widening of the pelvic girdle or the enlarged breasts women experience suggests the relationship between "less or more". Whereas the men don't experience outward physiological changes so the idea that it happens at a hormone level was fascinating.
Your question of whether less testosterone makes a man more or less of a man was intriguing. I guess the decrease in testosterone could cause behaviors that are commonly attributed to women such as caring for young like discussed in the article. I don't know if that makes him less "manly" especially since more and more men are the ones staying home with the children while their wives go to work. I think it is fascination that an increase in time spent with children was linked with this decrease in testosterone in men. It made me think about something I read about dogs and people and how petting and spending time with your dog can release the same chemical signal that makes a mother bond to her child. I think it is amazing how a simple thing like spending time with your child can lead to decreased testosterone and changes in behavior. This article was fascinating and i thought it raised a lot of really interesting questions.
ReplyDeleteThis paper about testosterone levels in fathers made me curious about additional hormonal interactions involved in child-rearing. I found an article that discussed prenatal cortisol ("stress hormone") levels in mothers and cognitive development in infants. Their hypothesis claimed that exposure of the developing infant to cortisol from the mother would impact their cognitive development, however, a negative prenatal impact could be moderated by a positive postnatal infant-mother relationship. They found that amniotic cortisol levels, as well as prenatal stress and maternal education, were significant indicators of infant cognitive development (Bergman 5) in infants with insecure maternal attachments. There was virtually no association between cognitive development and cortisol levels in infants with secure maternal attachments (Bergman 6). It seems that the environment a child is exposed to after birth has a more lasting impact on the child's development than prenatal conditions, which is beneficial for expectant parents considering the psychological stressors involved in preparing to raise a child. In connection to the other article, the testosterone levels in fathers may have certain implications regarding their masculinity in the eyes of our society, however, the quality and amount of time they spend building a relationship with their child is essential to the health and development of their baby, which supersedes maintenance of the fragile male ego.
ReplyDeleteReference article: Bergman K, Glover V, Sarkar P, O’Connor TG. Maternal prenatal cortisol and infant cognitive development: moderation by infant-mother attachment. Biol Psychiatry. 2010;67:1026–1032.
I think this situation is similar to the stress responses elucidated in the Sapolsky book. From the reading and in class, we learned that when the sympathetic nervous system is activated during a stress response, pupils dilate, cardiovascular tone increases, and digestion and reproduction are inhibited.
ReplyDeleteThe same could be true of fatherhood. The new father is constantly worried about making enough money to support the child, is stressed about whether or not he will be a good father, all while still trying to balance work life and maintain social relationships and a strong bond with his wife (my friend just had a baby a few days ago, and I know the father is chronically worried about all these things). Because the body is initiating a stress response due to these stressors, reproduction (and thus, the production of testosterone in the testes) is being inhibited.
I also believe that society is starting to accept the concept of “stay-at-home dads”. With the current economic circumstances, both men and women are in the work force; as such, the responsibilities associated with child-rearing are split between the parents.
Fatherly influence in a child’s life is also crucial for maintaining a stable home life for that child. Research shows that children reared in the absence of a father are more likely to commit crimes and drop out of school (for more details, see Think Criminology, John Randolph Fuller).
Fatherhood is clearly an important developmental factor in a child’s life (see above comments), and I think society is becoming more accepting of a father’s role at home.
This is a very interesting phenomenon. In an article I found on Pubmed.com, the testosterone level in mammals was credited with numerous morphological and behavioral traits. The one I found most pertinent to this study was reproductive competition. B.T. Preston et al, studied the effects of testosterone production on reproductive behavior in Soay rams. The study notes that testosterone production can be a costly endeavor on an organism. It states that studies have also shown that increases in competition for mates as well as increased interactions with females both lead to elevated levels of testosterone. The study B.T. Preston et al. conducted on male Soay rams showed that testosterone levels are also affected by seasons and rise during mating season.
ReplyDeleteBecause humans are mammals, males likely experience very similar effects to testosterone levels. However, because men with children are monogamous they probably see difference in testosterone levels. Clearly humans do not have a defined mating season. I wonder, however, if males that are not settled down have elevated testosterone levels because they are experiencing a sort of mating season while they are not locked down to women. I also think that the act of having a child puts the male in a state of stress, as Ashton mentioned above. This could decrease testosterone levels because, as the study mentioned, the production of testosterone is very costly. In order to deal with the demands of raising a child, the male may have to make a trade off and forgo testosterone production. Men who care for their children probably do not interact many other females and compete over them because they are so dedicated to their own family life. This, as stated above, would lead to lower testosterone production by the male as well. Overall, I think that the active participation of raising a child make the father more dedicated to his family and thereby makes him more monogamous. I think it is possible that this dedication is correlated to stopping competing for other females and may lead to the decreased testosterone levels in these active fathers.
References:
Preston, B. T., Stevenson, I. R., Lincoln, G. A., Monfort, S. L., Pilkington, J. G. and Wilson, K. (2011), Testes size, testosterone production and reproductive behaviour in a natural mammalian mating system. Journal of Animal Ecology. doi: 10.1111/j.1365-2656.2011.01907.x
Could the decrease in testosterone level by fathering children be an environmental adaptive trade-off? If you have already reproduced is the increased testosterone level significant for life?
ReplyDeleteThis is an interesting study. As we have learned in physiology, hormone levels are attributed to certain functions that the body must endure. Testosterone levels may be depleted because the brain realizes that the high level is no longer necessary.
I found a second article that could explain this decrease in testosterone levels. The article by Berglund et al, 2011 examined testosterone levels and physiological health symptoms in men. Men with higher anxiety test scores had lower testosterone levels. Being an involved father could definitely increase anxiety levels. This could possibly be one explanation for the lower testosterone levels seen.
ReplyDeleteLinnea Hergot Berglund, Hanne Sandberg Prytz, Aleksander Perski, Johan Svartberg. (2011), Testosterone levels and psychological health status in men from a general population: the Tromsø study. The aging Male, 14 (1): 37-41.
I would powerfully answer the main question that a most involved father is definitely no less of a man. Although I couldn’t personally quantify my levels of testosterone prior to and after birth of our children, one thing that I did notice about my personality is the tender loving care for my children. This is something that I obviously didn’t experience prior to our children. This observed change in my personality could potentially have some affect on levels of testosterone, but I would mainly attribute any changes in such levels to aging. Testosterone levels are highest around age 40 and gradually decrease from that point on (Testosterone).
ReplyDeleteHaving said that, I don’t necessarily notice any major differences in brain performance, bone and muscle mass, energy levels and other systems associated with the role of testosterone. But, I wouldn’t completely rule out results of the study. After all, I do find myself more and more in the loving, caring and sensitive side of my personality when I am around our children. And, since I spend a lot of time with our children and the remainder of the time continually thinking of them, these personality traits prevail, possibly affecting the overall testosterone levels.
References:
Testosterone. (2010). WebMD Man’s Health. Retrieved from: http://men.webmd.com/testosterone-15738