Metoidioplasty, sometimes referred to as a meto or meta, is an alternative to phalloplasty for Transmen. With the effects of testosterone treatment, the clitoris enlarges, over time, to an average of 4–5 cm. In a metoidioplasty the enlarged clitoris is released from its position and moved forward to more closely approximate the position of a normal penis. In some cases the urethra is lengthened to end at the tip of the neophallus. The clitoris and penis are developmentally homologous organs.
The labia majora (see vulva) can be united to form a scrotum, where prosthetic testicles (usually made of silicone) can be inserted.
This procedure is technically simpler than a phalloplasty, and has fewer complications. Surgery itself is also considerably shorter (1–2 hours vs. 8–10 hours) and it is much less expensive (perhaps US$15,000 instead of US$85,000). Unlike a phalloplasty, an erectile prosthesis is usually not needed to achieve erection. The clitoris contains erectile tissue which responds to sexual arousal. In most cisgender females, the clitoris is too small for the person to detect this erectile change significantly. In transmen and other female-bodied people whose clitoris is larger, this may be more visually apparent as it is in cisgender men.
If a metoidioplasty is performed without a urethral lengthening or scrotoplasty (formation of a scrotum from the labia majora), this is sometimes called a clitoral release. This is less expensive than a complete metoidioplasty but does not allow for urination (through the new penis) while standing. However this also offers surgery with less risk because the urinary system remains unaltered without a urethral extension and still affords some of the visual effects of a complete metoidioplasty.