Thread: Womb testosterone exposure, finger ratio etc..

There has been recent work into whether the ratio between a man's ring and index finger is indicative of the levels of testosterone that he was exposed to in the womb, and the researchers claim that this can also give us an indicator of his fertility, liability to heart attacks, depression etc, sporting ability etc.

However, I was wondering if anyone could elaborate on the importance of womb testosterone exposure. Is a man's fertility really set from the levels of hormones which he was exposed to in the womb, as I'd have imagined that later exposure (like the levels at puberty) would be more important - or are the levels of testosterone that a man is exposed to later in life also decided by the exposure in the womb?

Can we actually expect to believe that a man whose idex finger is longer than his ring finger to be 'less of a man'? Surely it is the testosterone which he is exposed to during life which is more important? Or can testosterone later in life (e.g. during puberty or taking artifically) not have such a profound fact on physical characteristics?

If we think of a man or boy who has an index finger that is longer than his ring finger is it really likely that throughout his life he is likely to be less fertile, more at risk from heat disease, less likely to make a top sportsman. Even if this particular male received higher amounts of testosterone during puberty than a male who had the favourable finger ratio?

What I'm really asking is if foetal exposure to testosterone is as important as Manning etc. make out, or if exposure later in life and at puberty is important (or is this too based on foetal exposure?). Can we expect males who had low womb exposure rates to be more likely to suffer from low testosterone levels in future? Does womb exposure have enough of an influence to make some men less 'man' than other men, or is it what happens after birth?

Would the all important penis size, for example, be based on womb exposure, or puberty exposure? Or are genetics far more important in general than womb exposure?

I'm partly asking this because the research (I know it is still fairly new and only lightly touched upon) seems fairly misleading. Why should the high testosterone ratio give higher chances of homosexuality if it also gives 'perfect alpha man' characteristics, and why does it differ depending on where peoeple are geographically located?

Thanks for any replies, I do find this topic interesting, and would love to hear some educated (or otherwise!) replies. I hope you don't find my ramblings too vague/un-scientific to follow

Any info on womb testosterone exposure and effects/lack of effect on later life I'm interested in.

BUMP.

Anyone? :-D

Would still be grateful of any responses

:?

first of all.. stop thinkin what testosterone would do to a womb, and start thinkin about what it would do in general..

testosterone is a hormone. it can pass the placenta. but it is mostly a male hormone, females still have testosterone, but a lot less (ofcourse).

Testosterone influences the production of sperm/muscle/stress 'action' hormones in a man.

i can't answer it.. but my idea would be that the kid would have a huge penis (boy or girl would be kind of the same). and a little more muscular forming. it'll probably have a heart attack before it get's born because it's body can't support the muscles.

still not sure.. hope it's helpfull

I think the key question here which leads easily to answer the rest is whether high levels of exposure in the womb have a major effect on 'masculinity' and most importantly whether they lead to high testosterone levels during puberty.
Now i'm no expert on biology, but as far as i'm aware most of the changes which make a man seem more masculine take place during puberty. The only physical indicators of masculinity i can think of which are defined before puberty are bone structure (especially in the face) and build... and finger ratios of course.
So if i'm right about that then we need to decide whether testosterone exposure in the womb effect testosterone producio later in life. I can think of a couple of mechanisms which could potentially lead to this. Although, whether they exist or not, i do not know.
The first is a genetic cause of high testosterone. If there is a 'gene for' high levels of testosterone in the womb in women that also causes high levels of testosterone in men then that would be an indirect link. I don't know whether there are any genes which combine these two effects in humans.
Or alternatively it could simply be that testosterone production in puberty is directly linked to exposure in the womb.
This probably doesn't help much, but i tried.

I just wonder whether pregnant women could manipulate the masculinity of male children by consuming tongkat ali during pregnancy. Tongkat ali has been shown in numerous studies to raise testosterone, and it does so in men and women.

Uterine testosterone levels are predominantly produced by the fetus. While there is circulating testosterone in the mother's bloodstream, it is the local production of androgens by the fetus that plays the most important role for masculization of the fetus.

The effects of hormones are complex and adding more of something is not going to give you the result you necessarily expect. For example, autism is 4 times more common amongst males, which would imply that there is something about male development that makes them more susceptible. One of the genes implicated in autism, RORA, is involved with the cycling of testosterone into estrogen.

Originally Posted by i_feel_tiredsleepy

The effects of hormones are complex and adding more of something is not going to give you the result you necessarily expect.

I wonder if excessive maternal testosterone could reduce fetal production of same? Could the compensation continue after birth?

Originally Posted by Pong

Originally Posted by i_feel_tiredsleepy

The effects of hormones are complex and adding more of something is not going to give you the result you necessarily expect.

I wonder if excessive maternal testosterone could reduce fetal production of same? Could the compensation continue after birth?

It's possible, but I'm not sure it would persist after birth. People who take steroids sometimes experience sterility because the gonads stop producing testosterone locally, and systemic levels of testosterone are not enough to stimulate the sperm production.

Too little testosterone messes up sterility, and too much does, too.

Pardon, if y'all wanted this thread to go dormant...
There is a supposed mild predominance of long ring fingers among lesbians and FtM transsexuals, indicative of prenatal testosterone exposure.

As opposed to a more typical woman's hand, which has a matching ring finger and index finger.

*shrug*. Not proven to have statistical validity yet, that I know.

To the 1st discussion, this was a correlation - a coincidence. Suggest you not assume and cause and effect.

Random - where did you hear that?

Originally Posted by Jorge1907

To the 1st discussion, this was a correlation - a coincidence. Suggest you not assume and cause and effect.

Random - where did you hear that?

The finger length thing is well established as linked to androgens like testosterone. We know this because it is sexually dimorphic, males have index fingers shorter than the ring finger, while females usually have approximately the same length or longer ring fingers.

There are correlations between the digit ratio and some features that suggest a link with fetal androgen exposure, but the causative link there is uncertain.

Originally Posted by Jorge1907

Random - where did you hear that?

Getting a bit personal there, mr Jorge...

I found some linky goodness after getting on my google-fu: BBC News | SCI/TECH | A finger on sexuality

The thing is about the survey described in the article...it seems to have been done on the cisgendered, and only covers orientation.
Gender identity is only tangentially related to orientation at best...

It is who you want to go to bed as opposed to who you want to go to bed with.

Transmen tend to go stealth very easily. As in they tend to be a little bit shorter (originally female build) and a little balder ( Barr bodies double the chances of getting the male pattern baldness gene ), but they generally don't get 'pegged' as having once not been physically female.
MtF's tend to be rather sturdy girls...they may have a harder time blending into the gender they've transitioned to.
Depends, of course.

The first time I met a bunch of MtF's I thought..."Wow, they all look like my mom..." Wal-Mart shoppers in practical tennies and simple helmet perms. So much for stereotypes.

Was curious = any references you can provide?