In general women have fewer opportunities and less encouragement. This is a well-substantiated and historical fact. Logically then, there are going to be fewer women that will excel in typically male fields until the balance is redressed.
As for there being more retarded men than women - I don't know I haven't reviewed the data, it certainly seems that way though.
Your claim is that men have fewer genes than women? That is false, they have more - they have the Y. Women inherit an X from each of their parents but only one set is expressed - the other is 'switched off' as with all other genes that come in pairs. The disadvantage for men is that if their only copy of a gene on X is faulty, they have to live with it (or die with it). They fly without a co-pilot, so to speak.
And in any event more isn't better, see Down's Syndrome.