If he was thinking of having a sex change in the future, this was certainly the wrong first step. There are reassignment surgeons who won't even accept patients who have had any prior genital surgery. Some transitioning people have just their balls removed to reduce the testosterone in their systems, but apparently that preliminary procedure messes up the scrotal tissue the surgeons need later in the creation of the vagina. So...do it all at once, or don't do it at all.