My Boyfriend doesn't Support Trans people.

I've been with my boyfriend for a year and 3 months now. We always make each other happy, we never got into a fight or an argument. There's always communication between us. However what bothers me the most is that recently he saw a post reguarding transexuality and he was just disgusted he even said so himself and it makes me disgusted that he even said that because I grew up in a respectful and accepting household with a accepting family and I'm just so..disappointed, I don't know how to feel. He supports homosexuality but I don't get how he doesn't accept transexual people. I scolled him saying "hey don't say that" and gave him a smack on his arm but not as hard. How should I view this? Should I bring this up? Because if I want a family with this man, I want him to be accepting especially it our children are different, I don't want him to belittle them.