No. I've simply studied this subject exhaustively and I've collected information from medical sources (web sites and medical books).
Yes, I have seen the assholes of pornstars who had a lot of anal sex. I used to watch them having it, in fact. I began to avoid the act entirely when I realized that it often results in visible, and unhealthy, changes to the anus (at least in porn).
Anyway, appearance is very subjective. I stand by what I said. My notion of a desirable appearance is based on the ideal anatomy. I didn't realize that and lacked the words to describe it until recently, though.
Erm... Have you thought about what you just wrote? The primary purpose of an anus is to play a role in defecation. It's not intended to be used for intercourse. The anatomy of the anus and especially the rectum makes that clear.
No. Like the vagina, the mouth
and the esophagus both are: very stretchable and durable; designed for rapid intake; abundantly lubricated (by saliva from the mouth and mucous draining from the sinuses -- and the vagina only naturally lubricates when aroused); and are lined by a multilayered, stratified squamous epithelium that resists abrasion. [1] [2] The mouth also has teeth to dissuade excessive abuse.
By contrast, the anus and the anal canal are not able to stretch nearly as much (although they can be gradually "trained" to stretch more over time, that carries risks as well and facilitates rectal trauma during insertive activities). Thus the anus and anal canal tear easily due to abrasive friction, despite also being lined by a multilayered, stratified squamous epithelium [2] for approximately 3-5 cm. [3] Beyond that short length lies the rectum. The rectum may be capable of stretching fairly well, but being lined by a delicate simple columnar epithelium, it also tears very easily. [4]
IMO, bacterial infections are also a much greater concern with anoreceptive activities than with vaginal or oral activities (for both partners). I won't even get into viral infections (STIs).
1.
http://www.courseweb.uottawa.ca/medicine-histology/English/Gastrointestinal/Gastro_Esophagus.htm
2.
Mucosal Immunology (2005) - Page 939
3.
Imaging of Anorectal Diseases (1998) - Page 6
4.
http://www.thebody.com/content/confs/aids2008/art48397.html
Your medical links are certainly interesting. I am not a big fan of anal - not really much of a fan at all, occasionally it's mildly arousing, but I prefer vag sex, by far - and definitely think it's overdone/overplayed in porn. And the rough stuff in anal is often just plain nasty.
That said, I have to wonder what your intention is here. Your argument sounds very similar to the rhetoric of the anti-gay crowd.
You talk about what the "purpose" of the anus is and what it's "intended" for. These are terms that strongly imply some sort of creator. If we're talking strictly about people and their anuses, then they can be used for whatever we wish, including sexual pleasure. But perhaps you were only talking about biological function. So, as someone else has noted, I don't think the mouth has a biological function of sucking cock. And having had my first serious girlfriend scrape the hell out of me (to the point of bleeding!) my cock with her teeth, well....
I'm just sort of suspicious of your motives, that's all.
But above and beyond all that, I wonder about your claims about the anus and stretching. I'm sure I'm not alone (at least as a guy) in having had shit-logs that were absolutely massive and, at least in girth, put pretty much any cock in porn to shame. I've NEVER seen a woman (never could hack more than a few secs of gay porn, so don't know about it) suck on a cock as big (in diameter) as some of my massive turds. So, even though my butt's never experienced anything other than poop, it apparently is able to stretch quite handily. Sure, it hurt a bit, but bleeding's been quite rare, and that seemed to have more to do with the hardness or texture of the shit more than the size of it. Sorry for being gross, but it just struck me that the whole thing about the ass not being able to stretch just seemed far-fetched.
Now, true, having 2 or 3 huge turds slide out is a different proposition than a cock go in and out vigorously for possibly many minutes at a time, but still...
