I have some stats for you, having recently compiled my 2010 business info. I could create a series of pie charts... but just telling you will be faster (I know I will spend too much time pondering pie wedge colors).
Category: Subject Matter
(not able to run)
(learning to run)
(easily run away from me)
And all this adds up to more than 100% because a shoot may consist of more than one subject, and it's just too complicated to sort it out.
44% of babies are Girls
56% of babies are Boys
No big diff between numbers of Girls vs Boys Tots and Kids
65% San Francisco
35% Everywhere else (from Santa Cruz to Tahoe)
Chances are, I'm photographing a Baby Boy in San Francisco.