&gt; 18 years<p>Why 18 years? You can harvest fertile gametes much earlier than that in an ordinary person. And with some unethical drugs you can reduce that age even more.<p>Just watch out you don&#x27;t end up selecting for early maturation :)<p>&gt; Everything I&#x27;m reading is saying the genes for IQ, as with most traits, are additive. And it really is as easy as putting as many high-IQ-associated genes into one genome as possible.<p>High IQ&#x27;s come with large tradeoffs. Foremost among them is a much higher rate of depression. Second among them is a reduction in socialization.