An 18-year-old boy died when doctors tried to create a vagina for him using part of his colon.
https://thepostmillennial.com/trans-teen-died-from-vaginoplasty-complications-during-landmark-dutch-study-used-to-justify-child-sex-changes
His colon was used because puberty blockers stopped growth of his genitals, which meant there wasn’t enough tissue to do the penile inversion surgery.