Yes - change "homosexual sex" to "non-procreative sex" and it's less controversial. What about just the human behavior of kissing? Perhaps it's a way of smelling each other's breath to check for disease signals, or sharing of pheromones, but I'm more inclined to think it's about virus transfer. I'd also presume that breast feeding might provide lateral transfer of beneficial genes via viruses that haven't "gone germline" yet. Viruses can also pass through the placenta to a fetus, and viruses can pass the blood-brain-barrier.
It's possible that a beneficial virus could get passed around that actually changes human thought/behavior. A rabies infection makes a person hydrophobic, but rabies isn't exactly beneficial (except maybe to bats).
Even more wacky - what if human rational consciousness is a function of one or many viruses that get transferred to embryos/fetuses/developing children? Perhaps over time some of those viruses have "gone germline" and are now HERVs. In that case God would not only be a viral meme, but also a molecular virus (or series of 'em) himself.