Prenatal testosterone linked to long-term effects in females with male twin
1–10 of 57 posts
Re: Prenatal testosterone linked to long-term effects in females with male twin
#2So if prenatal testosterone has such a deleterious effect on females, what effect does it have on males? How do all those metrics they measured for the girl half of the twin pairs compare to their sibling?
Re: Prenatal testosterone linked to long-term effects in females with male twin
#3So if prenatal testosterone has such a deleterious effect on females, what effect does it have on males? How do all those metrics they measured for the girl half of the twin pairs compare to their sibling?
"Unlike the females, the researchers found that male twins do not experience long-term consequences of being exposed to a female twin in utero."
Re: Prenatal testosterone linked to long-term effects in females with male twin
#4Similar for cows.
Re: Prenatal testosterone linked to long-term effects in females with male twin
#5Notably, they didn't control for social effects by looking at female and male sibling pairs with an age difference of 10-18 months. How much of this is parents favoring the male sibling?
Re: Prenatal testosterone linked to long-term effects in females with male twin
#6Notably, they didn't control for social effects by looking at female and male sibling pairs with an age difference of 10-18 months. How much of this is parents favoring the male sibling?
"To separate the effects of fetal testosterone from postnatal socialization, the research team repeated their analyses focusing only on female twins whose twin sibling—either twin sister or twin brother—died shortly after birth, and thus they were raised as singletons."
Re: Prenatal testosterone linked to long-term effects in females with male twin
#7Notably, they didn't control for social effects by looking at female and male sibling pairs with an age difference of 10-18 months. How much of this is parents favoring the male sibling?
"To separate the effects of fetal testosterone from postnatal socialization, the research team repeated their analyses focusing only on female twins whose twin sibling—either twin sister or twin brother—died shortly after birth, and thus they were raised as singletons."
This was my immediate concern as well. But they addressed it.
Re: Prenatal testosterone linked to long-term effects in females with male twin
#8Similar for cows. https://en.wikipedia.org/wiki/Freemartin
Critically, however, freemartins are a form of microchimerism. They literally have cells with Y chromosomes in their bodies, received from the male twin through the shared chorion. You're correct that there is a shared mechanism - they receive testosterone and anti-Müllerian hormone through this link, which are primarily resonsible for masculinizing the freemartin.
In contrast, this mechanism is thought to be only testosterone exposure in utero.
A better comparison, then, might be intra-uterine position in mice [1]. This is similarly a pure testosterone-exposure mechanism (no microchimerism). Briefly, mouse pups are arranged in linear fashion within the uterine horn, and so a given (non-end) female pup has 0, 1, or 2 males adjacent to her. There are clear physiological and behavioral differences in these 0M, 1M and 2M mice, corresponding to the level of testosterone exposure.
[1]: https://en.wikipedia.org/wiki/Prenatal_testosterone_transfer...
Re: Prenatal testosterone linked to long-term effects in females with male twin
#9So if prenatal testosterone has such a deleterious effect on females, what effect does it have on males? How do all those metrics they measured for the girl half of the twin pairs compare to their sibling?
"Unlike the females, the researchers found that male twins do not experience long-term consequences of being exposed to a female twin in utero."
Since the mother already have a lot of estrogen in her blood, it might simply be that the effect of a female twin does not impact the amount of circulating hormones. The effect of increased estrogen in the male twin similar to the increase in testosterone in female twins would be interesting, but it might just not be something that can occur naturally.
Thus if I speculate a bit, the reason for the non-symetric effect should be that the mother and father does not have symmetric roles during the pregnancy. If half the time it was the father that carried the child we would likely have seen a similar effect on males with female twins.
What would be interesting is if they looked at mothers with different levels of estrogen and see if that effects male offspring, in particular those with exceptional high and low levels.
Re: Prenatal testosterone linked to long-term effects in females with male twin
#10My girlfriend has a twin brother. Since they were born in Haiti and we live in the US I'm not sure how relevant this study would be towards her, meaning the socioeconomic changes between living in those two countries is pretty wide. How does prenatal test affect someone after they've gone through puberty? I just don't see how that can be attributed towards college graduation or marriage rates. Is that not a far reaching statement to associate the two?