Sex reassignment surgery (female-to-male)
Sex reassignment surgery from female to male includes surgical procedures that will reshape a female body into a body with a male appearance.
Many transmen considering the surgical option do not opt for genital reassignment surgery, though some do undergo a bilateral mastectomy, the removal of breast and shaping of a masculine chest and hysterectomy, the removal of internal female sex organs, along with hormone treatment with testosterone.

# Mastectomy
Many transmen seek bilateral mastectomy, also called "top surgery", the removal of female breasts and the shaping of a male contoured chest.
Transmen with moderate to large breasts usually require a formal bilateral mastectomy with grafting and reconstruction of the nipple-areola. This will result in two horizontal scars on the lower edge of the pectoralis muscle, but allows for easier resizing of the nipple and  placement in a typically male position.
By some doctors, the surgery is done in two steps, first the contents of the breast are removed through either a cut inside the areola or around it, and then let the skin retract for about a year, where in a second surgery the excess skin is removed. This technique results in far less scarring, and the nipple-areola needs not to be removed and grafted. Completely removing and grafting often results in a loss of sensation of that area that may take months to over a year to return, or may never return at all; and in rare cases in the complete loss of this tissue. In these rare cases, a nipple can be reconstructed as it is for surgical candidates whose nipples are removed as part of treatment for breast cancer.
For transmen with smaller breasts, a peri-areolar or "keyhole" procedure may be done where the mastectomy is performed through an incision made around the areola. This avoids the larger scars of a traditional mastectomy, but the nipples may be larger and may not be in a perfectly male orientation on the chest wall. In addition, there is less denervation (damage to the nerves supplying the skin) of the chest wall with a peri-areolar mastectomy, and less time is required for sensation to return. See Male Chest Reconstruction

# Hysterectomy and bilateral salpingo-oophorectomy
Hysterectomy is the removal of the uterus. Bilateral Salpingo-oophorectomy (BSO) is the removal of both ovaries and fallopian tubes. Hysterectomy without BSO in cisgendered women is sometimes referred to as a 'partial hysterectomy' and is done to treat uterine disease while maintaining the female hormonal milieu until natural menopause occurs.
Some transmen desire to have a hysterectomy/BSO because of a discomfort with having internal female reproductive organs despite the fact that menses usually cease with hormonal therapy. Some undergo this as their only gender-identity confirming 'bottom surgery'.
For many transmen however, hysterectomy/BSO is done to decrease the risk of developing cervical, endometrial, and ovarian cancer . (Though like breast cancer, the risk does not become zero, but is drastically decreased.) It is unknown whether the risk of ovarian cancer is increased, decreased, or unchanged in transgender men compared to the general female population. The risk will probably never be known since the overall population of transgender men is very small; even within the population of transgender men on hormone therapy, many patients are at significantly decreased risk due to prior oophorectomy (removal of the ovaries). While the rates of endometrial and cervical cancer are overall higher than ovarian cancer, and these malignancies occur in younger people, it is still highly unlikely that this question will ever be definitively answered.
Decreasing cancer risk is however, particularly important as transmen often feel uncomfortable seeking gynecologic care, and many do not have access to adequate and culturally sensitive treatment. Though ideally, even after hysterectomy/BSO, transmen should see a gynecologist for a check-up at least every three years. This is particularly the case for transmen who:
- retain their vagina (whether before or after further genital reconstruction,)
- have a strong family history or cancers of the breast, ovary, or uterus (endometrium,)
- have a personal history of gynecological cancer or significant dysplasia on a Pap smear.
One important consideration is that any transman who develops vaginal bleeding after successfully ceasing menses on testosterone, must be evaluated by a gynecologist. This is equivalent to post-menopausal bleeding in a cisgendered woman and may herald the development of a gynecologic cancer.

# Genital reassignment
Genital reconstructive procedures (GRT) use either the clitoris, which is enlarged by androgenic hormones (Metoidioplasty), or rely on free tissue grafts from the arm, the thigh or belly and an erectile prosthetic (Phalloplasty). The latter usually include multiple procedures, more expense and with a less satisfactory outcome, in terms of replicating nature.
In either case, the urethra can be rerouted through the phallus to allow urination through the reconstructed penis. The labia majora (see vulva) are united to form a scrotum, where prosthetic testicles can be inserted.