How does exposure to testosterone in the womb effect finger length?

Question

I read in Psychology Today (Feb 07) that, according to research, exposure to testosterone in the womb manifests through finger size; exposure to high levels appears as the ring finger being longer than the index finger, and exposure to low levels appears as the index finger being longer than the ring finger.

What are the biological mechanisms that would make this happen?
If you do not believe this conclusion, why not? Do you have information to discredit this conclusion? If yes, what is it?

Answer 1

testosterone lead to closure of bone epiphesis and prevent its further growth

Answer 2

Yes- this is true

In males high levels of testosterone in the womb lead to smaller index fingers, less social anti-social behavior and agression and very high levels autism

Both women and men have testosterone in their bodies
and high testosterone in the womb also may be the reason many more boys develop autism than girls

It is also been proven that girls with more testosterone in the womb at birth exhibit more male behavior tom-boy syndrome

Studies are below