Let me try to limit the discounting and justify those few:
- I am discounting revelation on the theory that reason and observation can be used to derive a natural law that even atheists would find persuasive.
- I am discounting some contraceptives, which have known side effects, in favor of others, which don’t, in order to focus on the contraceptive act itself and not the problems that some specific forms may exhibit.
That said, I am certainly all of the results including purely mental health, though I’m not aware of any side effects of condoms, which is why I chose that to represent contraception.
I am trying to find the natural weight of wrongs in an observable way that even an atheist would concede to. Obviously we are not here considering the weight of wrongs that might fall after death since atheists refuse to recognize this.
Hopefully this is clarifying.
This is a much trickier question but perhaps we can also look at this purely in terms of natural effects. Several people argued that the natural effect of contraception was reduced procreation. It makes total sense that life should favor procreation and that choices that go against that would frustrate this natural inclination. On those terms, absitanance seems to have the same effect as contraception.
Now if we could show that sex with contraceptives is not the same as absitanance in terms of observable results then we’d have an argument for distinguishing them. Sex with contraceptives is probably most common outside of marriage but we could say more simply that fornication has observable bad consequences for those involved.
But what about contraceptives in otherwise genuine marriage with the aim of limiting the number of children? One might argue that more children is always better, no matter what people might think. Or one might argue that contraception has observably bad consequences for the marriage, e.g. one or the other partner feeling a loss of genuineness.