Rectal Sex: Surveys indicate that about 90% of gays have engaged in rectal intercourse, and about two-thirds do it regularly.22 In a 6-month long study of daily sexual diaries,23 gays averaged 110 sex partners and 68 rectal encounters a year.

Rectal sex is dangerous. During rectal intercourse, the rectum becomes a mixing bowl for

saliva and its germs and/or an artificial lubricant,
the recipient’s own feces,
whatever germs, infections or substances the penis has on it, and
the seminal fluid of the inserter.

Sperm, which is immunocompromising24, readily penetrate the rectal lining (which is only one cell thick), and tearing or bruising of the anal wall is very common during anal/penile sex. Because of this, these substances gain almost direct access to the blood stream. Unlike heterosexual intercourse — in which sperm cannot penetrate the multilayered vagina and no feces are present — rectal intercourse is probably the most sexually efficient way to spread hepatitis B, HIV, syphilis, and a host of other blood-borne diseases.

Corey & Holmes (1980) Sexual transmission of Hepatitis A in homosexual men. New England J Medicine 302:435-38 ?
Manligit, et al (1984) Chronic immune stimulation by sperm alloantigens. J American Medical Assoc 251:237-38; Mulhall, et al (1990) Anti-sperm antibodies in homosexual men. Genitourinary Medicine 66:5-7; Ratnam KV (1994) Effect of sexual practices on T cell subsets. Intl J of STDs and AIDS 5:257-61 ?

http://www.familyresearchinst.org/2009/02/medical-consequences-of-what-homosexuals-do/