I know a girl with some health problems, she was one of those young women who always tried to get her tubes tied but was turned down. She became pregnant, didn't know it, and kept talking her birth control on top of all her other medicine. The ultra sound showed a severely deformed embryo, she said it looked like it had two heads, and she ended up aborting.
Well, after that, she tried to get her tubes tied again, but couldn't find a doctor willing to do it. This was in the state of Texas too, which is a very conservative, typically anti abortion state. She had an abortion, she wants her tubes tied, but she can't find a doctor in that state willing to do it... If she gets pregnant again, she's the type that will have another abortion and truth be told, she isn't the type of person who should have kids anyway.
Those doctors should consider if a woman wanting to be sterilized would or wouldn't be a good parent! I really don't think one's parenting skills is a factor they consider, it's marriage status, age, and how many children you have.