Your premise is flawed, here is a simplified version of what you are trying to say: If I cut the arms off two people and had them mate then obviously their children would be armless too.
No! Evolution doesn't work that way, and worst of all there was a thread just like this one which I went on a lengthy rant about just last night. So if you want to read about evolution use the internet, read Origin of Species, or read the Selfish Gene, (I know it is by Dawkins but it was back when his primary mission was to be a scientist, not spread the word about atheism) don't just come up with ideas about forcing evolution on people and then butchering the concept about as badly as saying that evolution moves in a set direction. So please a word of advice to anyone out there who wants to start a thread about evolution: Make sure you understand it otherwise all the bio majors will be angry and will summon C'thulu on you. Thank you for your time.
Oh and because I am really dedicated to the idea of procrastinating when I have a big ass Chinese project due tomorrow here is a quick synopsis of how evolution would work. You put people in room that is always 100 degrees, people start to live and work in that room, some get heat stroke, most are just flat out lathargic, and a few don't mind the heat. The latter group (Cold natured and hot natured people) At this point the people who don't mind the heat assimilate better and spend more time doing everyone's favorite activity: Screwing. They screw a lot and have babies, and pass on their heat resistant gene. But all this is predicated on the assumption that there are genes for hot and cold resistance and it isn't just something you learn to live with, and I really don't know that fact to speak decisively, but it seems probable that genes can have some influence to how well we adapt to certain types of temperature but this is just based off extremophiles and their environment, but even if we have a genetic disposition for doing better in the heat we can still survive in the cold thanks to that big four pound idea factory in our head that came up with the idea of a heater. Hooray!