Regarding human talent, we both can't prove either standpoint, so we'll just leave it at that.
Welfare is not the only solution to this problem. If minimum wage is not enough to allow a single mother to pay for child care, then we should just offer free child care, financed by taxes. Mom still has an incentive to work for a living, but is much better off. Scandinavian countries demonstrate that this works very well.
>Why should anyone in the US be guaranteed comfort when there are children begging in the street in Mexico or India?
Because as I said, the US as a society is incredibly wealthy. It's possible with a few political tweaks to fix this, and not a single person will be noticeably worse off. There's no real reason not to fix it, except for the extraordinary greed of a few.