Conjoined male twins one is gay

This involves concordance rates, the percentage of twin pairs where both twins exhibit the same trait. Insights from Identical Twin Studies Studies involving identical twins indicate a genetic influence on sexual orientation. If one identical twin is gay, there is a higher probability the other twin will also be gay, though not always.

A paradox is the occurrence of same-sex orientation in twins in that there is a higher level of concordance in monozygous twins compared to that in dizygous twins or non-twin siblings. If sexual orientation was entirely genetically determined monozygous twins would be expected to have identical sexual inclinations.

A conjoined twin has admitted he hid his true gender identity from his sister for most of his life. Lori and George Schappell were once the oldest living conjoined twins in the world and George's gender transition made him and his sister the first same-sex conjoined twins to identify as different genders.

Studies have shown that in identical twins, if one twin is gay (the term “homosexual” is used in clinical studies but is considered offensive, so I won’t use it further), then 30 per cent to.