Heck no 50's not to old. I think anyone who is a compassionate, good, love filled, hardworking human being is a suitable parent. There are many young women and men who are absolutely crap parents and do not deserve to have children in their care. I had my first child at 37 and would love to have more. I don't think my experience as a mom would have been as wonderful at an earlier age. As far as physical limitations go, I think that's up to the women carrying the baby and their doctor.