I was in cancer detection for over 40 years. The anus/rectum (mostly) is made up of secretory cells not squamous cells. Squamous cells are made for ‘protection’ (your skin is made up of squamous cells); the vagina is lined with squamous cells for protection against the roughness of intercourse. The delicate secretory cells that line just above the anal opening, and then all the way up the alimentary canal, are not made for roughness. And trust me, HPV in gay men is exploding due to the battering these cells are taking. (HPV doesn’t often affect squamous cells, just mainly glandular cells)This is the scientific view......the anal/rectal area was NOT meant to accept an erect penis. So no, anal sex is NOT good for the body, so is not ‘normal’.
Pretty much aligns with the first chapter of Romans.
It doesn’t say it directly like that. IIRC from Bio the lining in the human mouth is cuboidal squamous.
“AIDS will be cured when homosexuals learn the anus is for exit, not
entry.”
- Morton Downey Jr.