Well, umm, in actuality, if we're after any kind of stone-age replication here, there were no forms of birth control in the paleolithic era. I mean, other than abstinence, that is.
So, enjoying the primal/paleo lifestyle for fitness and nutrition doesn't entail having to avoid helpful technologies like condoms. I personally use Naturalamb because I don't enjoy latex or polyurethane; that, and they drastically reduce the numbing effect of typical condoms. Or, stated differently, they allow for a much greater degree of sensitivity during intercourse.