Test the waters a bit to figure out what they think of LGBTQ, specifically trans for your case. If they view it positively, go ahead, there is no reason to be scared. If only one does, talk to them and you two can come up with a plan to tell the other. If neither parent sees it positively or they view it negatively, just try to come out with caution. Sit down with whatever parent seems most supportive of you and try to explain the best you can. And again, you two can come up with a plan to tell the other parent. Either way, if they are okay with it or if there is a chance they aren't, just be yourself. If others don't support that part of you, learn to support yourself. Don't change for others. If you are trans, you can own that without the support of others.
