The results of a long-term study indicate that stay-at-home moms are not as healthy as married working mothers. SAHMs had the poorest overall health, followed by single mothers and the childless. Unclear if the study included lesbian moms.
The researchers hypothesize that an employed mother’s multiple roles keep her in better shape. I dunno. For me, running around the playground with my son keeps me much fitter than sitting at a desk all day. (Then again, I’m usually the only mom doing chin-ups on the climbing bars.)