Male Hands Vs Female hands... why different ring/index finger size?

Question

Why do male & female hands differ in ring/index finger length?

In 98 to 99% of males (human) the ring finger is longer than the index finger but the reverse is true for the female hand. Lay your hand flat on your desk (fingers together) & if male, the ring finger is probably longer than the index finger... for females the index finger will be longer (make the boy scout sign & look at your fingers.) Is this a gene, or is it caused by hormones, created in the womb? I have looked for links on this subject, but found none, can you help? Is this true at birth... I suspect it is!

I notice the dominate hand (right handed or left handed) "appears" to be slightly longer in ring finger to index finger ratio. Could hand use have something to do with this ratio too? I've asked this question a number of times & never gotten a serious answer. Does anyone know if the neanderthal's hand had a simular confirmation? Chuckle, the medical & biology field seem know nothing about this.

Answer 1

I have heard that it is controlled by male hormones which seems to be what was suggested.

I wonder if it could have evolved to hold spears or other jabbing weapons.   Our ancestors may have thrown hand axes for over a million years and both actions might benefit from a more symmetrical grip.

Answer 2

It's an effect of in utero hormone exposure. The more testosterone, the longer the index finger, more estrogen gives you a longer ring finger.

It's common for g*y men to show a feminine digit ratio, and for lesbians to show a male or intermediate pattern.  Apparently a very long index finger is a sign of particularly good lung development in males.

The wiki page is actually pretty thorough.

http://en.wikipedia.org/wiki/Digit_ratio

I think that their being a slight variation from one hand to another is just random though. The palm creases aren't the same either.

I only know about Neanderthal toes being different to African, the second toe is longer than big toe in them (and me). I've never seen a mention of digit ratio in them.

But, I've dug up some links to pages you might find interesting involving Neanderthal hand function and some on digit ratio, one telling the gender of cave artists by the finger lengths on the hand prints.

http://www.pubmedcentral.nih.gov/article...

http://lib.bioinfo.pl/pmid:16191608

http://www.waspress.co.uk/journals/befor...

http://www.femininebeauty.info/peter.fro...

http://www.springerlink.com/content/jv1k...

Answer 3

Good question!

I found the answer. :-)

To sum up what I read, animal models have indicated that androgenic steroids acting before birth might influence if you're a man or woman. So yes, there is a genetic difference from birth as to what gender a person will be and surprisingly the finger length is different in men and women.

Answer 4

good question

Answer 5

Seems like they would have to take the age of the mother and/or father into account.  More children could point to older parents. Don't hormone levels start to equal out as we get older?  s*x difference is less pronounced in childhood and older age. Thoughtful question.  Thanks.

Answer 6

i don't know ask a easier question next time