To Debbie Codding

-I don't have my book at home, so I am doing this from memory.  According to
Ruth Lawrence in Breastfeeding: A Guide for the Medical Professional, the
proliferation of mammary tissue is fairly complete by the 16th week of the
mother's first pregnancy.  It is possible that the mother can produce milk
anytime after that, although with increasing amounts occurring throughout the
pregnancy.

I'll double check my reference if you like, just e-mail me.  Hope this helps