Tink, you don't stop planning even though he could get cancer or be hit by a bus, right? It may be in the back of ones mind that "things" can happen but they are so unlikely that we don't worry about them. If transsexualism is your greatest fear, it's either a) he's not, so don't worry or b) he is and there is nothing you can do about it, so why worry? By the way, it's a) he's more likely to be hit by a bus.
water off a ducks back....