Only a small number of people with gender dysphoria have surgery to align their bodies with their desired sex — but the rate of complications is high.

One of the largest surveys of trans adults earlier this year indicated that one in six (16 percent) go under the knife to alter their physical appearance.

But research suggests that up to half of trans men and women suffer post-op issues or pain so severe they need medical attention or additional surgery months later.

The complex operations involve crafting the genitalia of the opposite sex using veins, arteries, muscles and skin from other body parts. The surgeries are risky due to surgeons having to connect delicate and complicated networks of blood vessels, as well as creating the ability to urinate.