"Come on Jack, hands have myriad uses, reproductive organs only one."

Oh come on! Humans, unlike animals, can have sex 365 days a year and several times a day, while the female ovulates and can conceive about thirteen times a year, for just a few days each time.

Do you see where this is going?

Nature doesn't place limits beyond what is possible, and sex is possible for humans whether conception is possible or not.

Maybe sex for pleasure is about bonding with occasional opportunities for procreation.

Kind of alters the argument, doesn't it, for all but dried up, past it puritans?