Thanks I needed that with my afternoon coffee. Now to clean this keyboard and table. 'Free kids!' begs the question for me how many economists donate swimmers.

There are widespread claims floating around the pop-sci-o-sphere that intelligence is disproportionately inherited from the mother (see, e.g. here ), which would suggest the important thing is getting smart women to donate eggs, much more than getting smart men to donate sperm.

Although, I see that when this topic was briefly raised at the skeptics stackexchange, the evidence appeared to be lacking.