Evolution and Technology might be interconnected more than we thought

Normally, evolution takes place oven long periods of time, and in rather isolated populations. Isolated, meaning not breeding with organisms of the other population. Over time, those two populations each develop characteristics that make them more fit to survive in their respective environments. Now, I'm not talking about little body-builder squirrels kind of fit, but fit as in able to evade predators, gather food, and reproduce.

But now, things are changing much more rapidly. In 1850, the average man stood 5' 7" and weighed 146 lbs. by 1980, men were standing at 5' 10" and weighing 174 lbs. From the evolutionary standpoint, that is no time at all. So how did we change that much? We thought our way into evolution.

Thanks to this nifty bit of brain called the forebrain, we can focus our thoughts on more than 'Food', 'Hunt', and 'Sleep'. Now, we think 'Build', 'Work', and 'Change'. This has resulted in us as a race doing things so simple as attaching a sharpened stone to a stick, all the way to things as complex as putting people on the moon and bringing them safely home. What does this mean for us?

Well, first and foremost, it means we live longer, and better, than we have in the past. That in turn allows us to make the lives of our posterity better, and that process continues on and on. Couple this with inventions allowing us to genetically modify organisms, we could eventually be producing tailor-made pets and children. So other than the morals behind it, what are the problems?

First, we don't know all of the effects of genetic manipulation. Could be that memory and intellect are directly related, and improving one improves the others capacity. Could just as easily be that by driving up our intelligence, we drop our memory. We just don't know. The second, and potentially far greater problem, is that as we begin to alter our species, we won't all alter our children the same way. Some parents will elect for enhanced brain power, while others will encourage strength. Continue that path for a few hundred, maybe thousand, years, now we are looking at having many different strains of Homo sapiens walking around on earth. And there's absolutely no way to guarantee that those new strains will be able to produce viable offspring.

That means there are many factions of people on earth, which to me sounds like a recipe for war.  Or it means the human race will slowly drive itself to extinction.

I don't particularly like either of those options.