Why wait two weeks for hatchlings when you can get results in the blink
of an eye? (Well, two or three blinks with a 14.4) I've found this
excellent D. melanogaster breeding simulator at:
It recreates almost every detail with incredible accuracy: sex-linkage,
homozygous lethals, epistasis, recombination frequencies... Sorry if I
sound like an advertisement (I'm not! :) Really!) but it is a great
place if you are a student working on a genetics unit.