Correct. According to what I've read of biology, there are two things to determining sex itself. And it's sometimes separated into something called sexual characteristics, which is your private parts, and something called secondary sexual characteristics, which is pretty much just your appearance. Transgender people who haven't had the operation done, but take hormones, are changing their secondary sexual characteristics. And in a lot of ways, I feel that the secondary sexual characters can be more important than these "main sexual characteristics", ie the private parts.