So, our early ancestors had sex specifically for the purpose of procreation? As in, they were thinking about having kids and made the conscious decision to have sex, as opposed to being tricked by the mechanisms of their bodies into engaging in acts they enjoyed that consequently resulted in the birth of a child?Something like sex with contraception would be on the same level with homosexual sex, that is, having sex purely for pleasure.
Here's what I think. I think straight people have sex purely for pleasure. Randomly, they ended up with kids as a result. Now, out of guilt due to social conditioning which attempts to control sexual behavior, they need to justify their pleasure, and so they point to the end result of that behavior, which is procreation. But I really don't think that straight people, whether in modern times or prehistoric times, engaged in sex expecting and wanting a kid each and every time. Procreation is a consequence of sex, but it is not the primary motivation for most people when they choose/chose to have sex.
What does a person's sex life have to do with the decision to adopt and/or raise a child? When a straight couple has a child, you could say that their sexual behaviors directly contribute to that child's existence. But when someone adopts a kid, his/her sex life has nothing to do with that kid having been born. It doesn't matter if an adoptive parent is straight, gay, bi, lesbian, trans, intersex, or even asexual. An adoptive parent's sex life is not connected to the birth of the adopted child. In fact, the role of an adoptive parent is to assume a role abandoned by the biological parents, whether by choice or by some uncontrollable circumstance. Any adoption is a redefinition of the traditional role of a parent because the traditional roles of parenthood belong to the biological parents. However, sometimes the biological parents die, or are otherwise unfit to raise their own children. In that case, the situation calls upon society to redefine that role.And as for the second point, no it isn't, because liberation requires redefining the role and usage of sex, which is what the acceptance of homosexuality and sexual deviance entails. It's a liberation in that we're opening the door to more uses of sex to become accepted.