I thought they determined already it was a hormone released in the womb during pregnancy, similar to left-handedness. That’s how you can get identical twins, but one is straight and the other is gay.
That is a pretty self-contradicting statement in multiple ways.
Not necessarily. My twin boys who just turned 3 are identical according to a genetic test, but were in different sacs with different placenta. This is uncommon, but not THAT uncommon. I think it's not unreasonable that they would have received different amounts of chemicals. They are certainly very similar, but have many differences, and were a pound apart at birth.