Ends up that over history, there have been hundreds of medical 'reasons' given for justifying them. The ones given here already are just the most recent. I'm sure in 50 years there will be completely different and new 'reasons'.
Here is a list of 'reasons' overall:
Circumstitions
(''Reasons'' Given for Circumcising a Male)
"If it seems too good to be true, it probably is"
The variety of reasons given for male genital cutting (and the irrationality of most of them) is amazing. Put them all together and your mind will boggle. When I started collecting them, I thought I'd find about 30 "reasons", and that seemed strange enough. But between 1998 and 2001, this list grew to 300, and the differences between many of them became too subtle to be interesting. You may see the complete list, but here are the major categories, in approximate order of frequency, with some choice examples.
1. Conformity
Because "a boy should look like his father"
Because all the nice families are having it done.
Because it is a cultural norm.
2. Medical
To prevent or cure alcoholism, arthritic hips, asthma, balanitis, blindness, boils, cervical cancer, chicken pox, epididymitis, epilepsy, gallstones, gout, headaches, hernia, HIV, hydrocephaly, hydrocoele, hypertension, insanity, kidney disease, kleptomaina, leprosy, moral depravity, paraphimosis, penile cancer, plague, phimosis, posthitis, prostate cancer, rectal prolapse, rheumatism, schistosoma, spinal curvature, stomach infection, tuberculosis, urinary tract infections and/or yeast infections.
3. Religious
To draw down the Divine light, bring down the soul of holiness into the body...
Because it is a good Christian thing to do.
Because Mohammed was "born circumcised".
Because a baboon the Egyptians considered sacred is "born circumcised".
4. Sexual
Because his mother and her friends prefer circumcised men for sexual pleasure.
Because it enhances sensitivity.
Because it reduces sensitivity.
5. Aesthetic
Because it makes it uniformly pink.
Because it makes the penis look more modern
6. Irrational
Because the foreskin will fall off if a baby is put into a hot tub of water for a bath.
Because it only seems natural.
To prevent "psychological trauma due to castration anxiety".
7. Instructive
To teach him that the world is a painful place.
8. Submission
Because his master ordered it.
9. Pre-emptive
Because it will have to be done sooner or later.
10. To benefit someone else
To provide collagen for cosmetic surgery on lips and cheeks.
11. Cleanliness
To stop him dribbling when he pees.
12. Control
"Because [my sister's] doctor said having his glans exposed would help calm him down a little".
13. Revenge
Because his mother had an episiotomy. ("I was cut, why shouldn't he be?")
14. Financial
Because a military surgeon "wanted to get back into practice because she could get $100 apiece for them in private practice."
15. Initiation
To prepare him to receive tribal secrets.
To separate him from his mother.
16. Non-conformity
Because he belongs to the upper class.
Because "I kind of think it is 'American'... in the early years of this great nation, we took pride in BEING DIFFERENT thon ether nations".
17. Concealment
To pass as a Muslim.
18. Punitive
To spite his absent/divorced father.
To get even for having been raped as a teenager.
19. Symbolic
To make the penis look like that of a kangaroo.
20. Status
Because he will be prevented from speaking in public if his (Samoan) father is intact.
"If you ain't circumcised, you ain't shit."
Because he's an orphan.
21. Reproductive
To prevent infertility.
22. Reward
To use his foreskin for a dowry.
In exchange for not having to change his diapers.
23. Convenience
Because "we just do it. It's better this way." (to a man being operated on for kidney stones)
Because he is under anaesthetic already for another operation.
Because his mother was having another baby, so they could go in together.
24. Iatrogenic
To treat paraphimosis caused by improper insertion of a catheter.
25. Ignorance
To make his penis bigger.
"...to protect the boy or man from the psychological trauma of an abnormally small penis"
Because it's a law.
Because his mother had never seen an intact penis and thought it was deformed.
26. Mistake
Because of an "accident on medical records..." According to the "paperwork guidelines, I was not supposed to be Circ."
27. Pity
Because the father "just didn't want to argue with her after she'd been through all that suffering."
28. Prudery
Because his mother thought that cleaning him was too much like masturbating him.
29. Sympathetic Magic
To give him the appearance of permanent arousal.
To remove the female element from him.
30. Vague
"She's not even clear on [it]. She just wants it, you know."
"
thought [he] might as well be circ'd."
--------------------------------------------------
A list of over 300 can be found at: http://www.circumstitions.com/Stitions&refs.html#medical