Can transsexuals become pregnant

That would depend on the type of transsexual they are.

A transsexual woman can never become pregnant, though she can father children before taking hormones and getting surgery. They can never get a womb, though uterus transplants and ectopic pregnancies have been considered as possible options, but both are considered way to dangerous to attempt.

A transsexual man can become pregnant if he gets pregnant before taking hormones and getting surgery.