'Basic human nature'is a phrase that assumes a lot of things. How would you characterise this phrase in more detail, as it pertains to this topic? And how would you justify such claims?
Basic human nature is to further the species through population growth. It's literally the only thing that everyone can agree on as being "why we're here". Every instinct ingrained in every living creature is to produce offspring.
Telling people to stop producing offspring goes against basic human nature, and requires a pretty educated populace in order to understand why they have to stop this instinctual process.
Sex is fun irrespective of it causing breeding. They are evolutionarily linked, but the have no moral relationship within the human brain. The desire to have sex and the desire to have children are for most people, completely independent desires.
And for what it's worth, humans have no obligations to our evolutionary past. "How we evolved" has no direct bearing on what we want (or 'are meant') to do with our lives. It only determines what we are circumstantially capable of.
EDIT: Here's a nerdy analogy for you. There is a relationship between the "programmer's intent" and the "binary program". But that relation has no bearing whatsoever on the relationship between the "binary program" and the "runtime behavior" of that program. These are independent relationships analgous to the relationship between "evolution" to "individual" and "individual" to "individual desires." (The feed-back which would link these -- from "runtime behavior" to "programmer's intent" -- only happens when the programmer is working, long before you end up with the binary you have when you run the program. In fact, this feedback is only ever employed to generate a completely new binary, never to modify the prior one. Thus ensuring that they cannot be co-dependent relationships, and thus evolution has no ability to determine individual behavior past the point of your DNA being fixed at conception.)
I think you're missing the connection. Sex is fun because evolution selects for things that improve reproduction. People that have fun having sex are going to reproduce a lot more than people who don't have fun having sex.
I'm not missing the connection, I am saying explicitly that is is unimportant. The only reason it wouldn't be is a lack of suitable birth control access.
Yet if you don't want to have sex, you don't have to, despite any evolutionary pressure to do so. So evolution is not a consideration when trying to determine whether you want to have sex.
Evolution certainly is relevant if you explicitly think about your own evolutionary origins and what strategies worked out for your ancestors, when deciding what to do yourself.
