Last few weeks

Goose I'm sure there is a lot to that. Look up sex linked chickens and see if that's not basically the same thing. If so it's easily proven in chickens. I know a lot of the Aussie's used to claim that if you use a bull bitch and breed to a Dane or stag you will get a little shorter legged and bigger headed dogs than if you use the stag or dane female and the bull male. I've not done breedings that would yeild such clear evidence, so just be speculation on my part of I was to say. I don't really doubt it though. The chicken deal is some pretty hard evidence to support you question if indeed sex link is same thing your referring to.