This does not follow, and is a very simple (and incorrect) view of genetic propagation. There are many recessive genes that are persistent in the genome despite offering no reproductive advantage and in some cases a huge reproductive disadvantage. Relevant to homosexuality in particular, the in utero environment during fetal development can impact whether or not a latent gene is expressed in a meaningful way. There is some clinical evidence that homosexuality may in part be caused by environmental factors during fetal development; whether or not this interacts with recessive gene expression is unknown but certainly plausible. Homosexuality is not unique to human animals and very similar expression patterns have been widely documented in other species, including environmental manipulations impact on the expression of homosexual behavior in a population. Any genes that may be involved could therefore flourish unimpeded under many conditions, only resulting in a terminal non-reproductive state under very specific conditions. This is similar to how recessive genetic diseases are persistent in a population even though certain expressions of those genes may kill the person before they reach puberty.