A biological genital deformity doesn't make it the rule.
Changing the language from "hermaphrodite" to "intersexed" won't legitimize transexual behavior (or vice versa) on some biological level.
It's wrong to conflate a biological deformity at birth with being transexual. They are not the same.
It means there is no rule. This population of people is bigger than the number of people with cystic fibrosis, for instance.
Also, I don't think changing the language is about legitimizing behavior. It is about describing people in a fair and respectful way, just as with the change in language from colored and Negro to African-American and black.
Lastly, I wasn't conflating "a biological deformity at birth with being transexual." But that is one of many factors which could cause somebody to identify with a gender which differs from the one which they were assigned at birth. And people need to be more aware of things like that.