Hmmmm... I thought I remembered seeing a pro BF t-shirt that did say something along those lines, but this wasn't it. Besides not really getting across a clear message, it is just plain ugly.
It looks like all the seller's t-shirts are unattractive and stupid. I don't mind the knocked up one though, as I jokingly referred to myself as knocked up throughout my pregnancy (planned, and after we were married). As the daughter of a woman who was "knocked up" twice during the sixties and seventies, and suffered the social consequences for it (including having a nurse threaten to have her thrown in jail for being pregnant and unmarried), I try to take back that word and use it in a positive way.