Even if you have a perfect organ match you will still have to be on anti-rejection drugs until the day you die. Even then it is not uncommon for organs to be rejected anyways and they have to be removed before the host kills itself. Now imagine how a body would react to a completely alien organ that it was never intended to have. I think the first attempt was in Hueland, and as far as I know they died horribly, which I consider a successful operation.
Men are better than women at nearly everything, but the tradeoff is that we will never create life. Our hips are too thin, even the worst cases of gyno won't produce an adequate supply of milk, and most importantly, we don't have the extremely complex set of hormones that occur in a pregnant mother that medical science likely won't understand for centuries. You can buy tranny pills made out of horse piss, but you will never get pregnancy hormone pills.
Even if you find a Tzimisce flesh crafter to undergo the operation with no side effects, what would happen then? First of all, you'd need a baby sized dilator to give birth through your stench trench, which means you'll likely undergo a caesarian. The child will never truly be yours, it will be the donor's child and DNA, unless you used your saved your sperm in a spermbank before your trooned out, in which case it is everyone's solemn duty to destroy civilization.
It is truly a sign of man's folly that we would even allow a mentally ill troon to try to give birth when over 50% of the population can do it infinitely more efficiently and safely.