>being a homo is genetic
>its okay to be a homo now
>homos get with men instead of marrying women and reproducing then getting side homo action
>the genes that result in the various flavors of phenotypic homosexuality are rapidly depleted from the pool
>brief 100yr zenith of homos
>then 1 million year nadir

Scientifically speaking, is there any other outcome? Sure a random mutation could bring it back, but not on the scale of millions of people.