Original sentence: He developed new surgical techniques for sex reassignment surgery: Metoidioplasty, an operation for  female-to-male sex reassignment; and the recto-sigmoid colovaginoplasty, an operation for male-to-female sex reassignment
Edited sentence: He developed new surgical techniques for sex reassignment surgery: Metoidioplasty, an operation for female-to-male sex reassignment; and the recto-sigmoid colovaginoplasty, an operation for male-to-female sex reassignment