As I noted in the other post, the White Ajah has already deduced all this. It's more a matter of when they'll bring this back on the agenda rather than if they will. Given the relationships between Asha'man and Aes Sedai, it's also only a matter of 15 years or so before it's obvious to everyone that channelers together give birth to channelers.

Even during the middle-ages, horse and cattle breeders had worked out empirically how to cull out or fix recessive traits, long before anyone knew anything about genes. Breeders in WOT know this too, it's mentionned in the series; the Whites deduced correctly this would apply as well to the ability to channel.

Of course, Rand/LTT will shortly have 6 babies from two different wives on the way. It would take a little miracle for him not to let slip the kids will be channelers (not necessarily "on screen", in fact I'd be surprised the issue of genetics is raised again before the end... well, it's always possible Elayne/Rand or Rand/Aviendha will have a long conversation scene in need of filler material I guess).