I can see no compelling reason why a physically disabled person shouldn't be allowed to have a child. If they think that they are able to take care of the child, then they should have one and make that decision for themselves. It's dangerous territory when we start telling certain groups that they shouldn't have the freedom everyone else has.
I feel that any person who has a physical disability which in a the case of a female, would allow her to have a healthy pregnancy and delivery and to care for the child they should absolutely be given that opportunity, Any adult who has learned to accept and build their life around a physical disability would be an extraordinary role model for any child. I do not believe it is not the right of the government or general public to determine a persons right to procreate. If it's meant to be who are we to question?