Re males getting endo : I read far and wide when I was in the throes of it, and one book that I still have is 'Endometriosis and Fibroids' written by Dr Sarah Brewer with the National Endometriosis Society. Published 1995, so almost 30 years ago.
She goes through the reproductive anatomy and how it differentiates in utero. Mentions:
- 'In rare cases, men receiving hormone treatment for advanced prostate cancer have been found to have endometriotic tissue, and this is thought to come from the vestiges of the Mullerian duct(s).'
Having just gone through what Mullerian ducts are and how they cease to grow in male embryos once their testosterone production starts.
So yes, it happens. Just very rarely.