Patients can choose the penis size they want up to 7 inches 18 cm long with a circumference up to 5. Much longer and much larger is possible but is usually inadvisable. For young boys, a longer then normal penis for the particular age of a child is created because a neophallus does not follow normal genital growth in the child, only somatic growth, so must be adult-size from the start. For decades, surgeons have been using a radial muscle from the forearm of patients to create a rather ineffective neophallus. This old technique, sometimes called forearm free flap phalloplasty, is still widely used by plastic surgeons.