I think the legacy rules specify which lot you are supposed to buy, and a legacy is supposed to run to 10 generations if you complete the whole thing. Personally, I prefer a male founder because his career isn't interrupted by pregnancy, but it's up to your preferred playing style. I find that themes make it easier to pick names. I guess the best advice is to keep the rules handy (bookmarked?) if you plan on playing by the rules, and otherwise, don't stress too much about it and just go with what's fun to you. It's a game, after all!