This, from a posting by Sheldon Brown about ten years ago....  (highlights mine)
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Rafael Aviles wrote:
>  
> Riding while pregnant is not too difficult. Getting pregnant while riding is,
 of course, a bit trickier...
 
My buddy, John Allen (http://www.bikexprt.com/users/jsallen/) used to
theorize that this might be possible on a recumbent tandem...and that one might
be able to finance it by getting funding for "recumbent dna research."
 

Paul,
 
You know some Japanese believe concieving under the arora borealis will give their child unique attributes. Wonder what magical qualities might impart to a young un conceived on a recumbent whilst burning up the road. Maybe a wildly hyperactive child, with a bullet shaped head,  that screams everytime you pass by a bike shop, has massive thighs and bears a faint resemblece to Greg??