KAMPALA, Uganda » Human Rights Watch is urging an end to “forced anal examinations” with a report documenting them in eight countries, mostly in Africa, saying the practice is based on flawed ideas about supposedly proving homosexual conduct.

In a report released today, the advocacy group calls the examinations “a form of cruel, degrading and inhuman treatment” that amounts to sexual assault, violates international conventions and could rise to the level of torture.

The report draws on interviews with 32 men and transgender women subjected to the exams in eight countries that ban same-sex conduct: Cameroon, Egypt, Kenya, Lebanon, Tunisia, Turkmenistan, Uganda and Zambia.

The report says the exams are rooted in “discredited 19th century theories” that homosexuals can be identified by characteristics of the anus.

A Kenyan court recently upheld the use of anal examinations to determine a suspect’s sexual orientation, dismissing the argument that the procedure amounts to torture and degrading treatment.

A group of homosexuals in Uganda will soon launch a court case against the procedure because it violates the country’s bill of rights, said Frank Mugisha, a gay leader who said he was aware of many such incidents.

“It’s very degrading,” he said.

Although some cases involve rape, many involve consenting adults targeted by the police, some of whom try to extort cash from suspects, Mugisha said.

The subject of homosexuality is taboo in many African countries. In 2009, a Ugandan lawmaker introduced a bill that prescribed the death penalty for some homosexual acts. A less severe version passed by lawmakers was rejected by a court as unconstitutional, amid international pressure.

Many homosexuals live secret lives, afraid of beatings and other acts of violence if they are outed.

Associated Press writer Jamey Keaten in Geneva contributed.