But epigenetic changes during foetal development could effect the likelihood of being successful at passing ones genes along at all, although I've no idea how y

But epigenetic changes during foetal development could effect the likelihood of being successful at passing ones genes along at all, although I've no idea how you'd manage to isolate or replicate these effects in any scientifically useful fashion. Someone in these discussions always brings up epigenetics at some point, its impact there far exceeding its impact on population genetics I would guess :) Nobody ever talks about genetic drift or gene flow however, probably because despite being actual things that affect population genetics talking about "nearly neutral drift in small populations" is really hard to wedge into an ideological shouting match dressed up as a scientific debate.