Answer:
Right now they don't. At the moment the only path available to women born transgendered is to take hormones, possibly have a mastectomy and use artificial aids for the act of sex.
In the near future (between 5 and 30 years) doctors will be able to grow organs for us from our own cells and we will not reject them; it's us! In a similar way to what a man born transgendered will go through, testes, a penis, a prostate, scrotum and tubes. They will be able to remove the present organs (uterus, vagina, fallopian tubes) and implant the new male organs.
The reasons that male to female transgendered surgery (SRS/GRS) appears to be ahead of female to male lie in 2 things: 1) it's easier to remove flesh than it is to add it and 2) there have been a lot more m2f surgeries than there have been anything for f2m. When more women come to the medical establishment wanting GRS of some sort, then they will get more attention: the squeaky wheel gets the grease (whether it deserves it or not.)