It has been done: the first baby has been born after a womb transplant. Swedish doctors have transplanted a womb into a 36-year-old woman who subsequently got pregnant and give birth to a son. Though being born prematurely, he is healthy. You could read more in The Guardian.
In Sweden nine women have received a uterine transplant, with the intend of getting pregnant very soon. According to the BBC the nine women were either born without a uterus, or had their own uterus been removed for medical reasons. Uterine transplants are a new area of medical science, earlier attempts in Saudi Arabia and Turkey have failed.
But suppose that the Swedish experiment works, after all organ transplants have a history of failure and ultimate success, then it will be possible to transplant uteri into males as well. Most academic discussions about male pregnancy, are about ectopic pregnancies (i.e. implantation of the embryo outside the uterus). But since ectopic pregnancies are usually lethal, no serious attempt has been made to induce such pregnancy in a male. Only a few ectopic pregnancies have resulted in live birth.
However, with uterine transplants the whole problem of ectopic pregnancies is avoided. If successful in women, there’s from a medical point of view no reason to refuse such treatment to males. Whether transplanting uteri into males is desirable, is a totally different matter.