Defying protests from rights groups, criticism from Western donors, and a U.S. warning that it will complicate relations, Uganda's president signs a law imposing harsh penalties for homosexuality Monday.

Ugandan President Yoweri Museveni.

(SOUNDBITE) (English) UGANDAN PRESIDENT, YOWERI MUSEVENI, SAYING:

"(For) Someone to be homosexual it's a combination of some genetic, but mainly external factors, like influence and so on and so forth."

Homosexuality is taboo in almost all African countries, and illegal in 37.

(SOUNDBITE) (English) UGANDAN PRESIDENT, YOWERI MUSEVENI, SAYING:

"We do not want anyone interfering with our internal affairs, finished."

The law comes a week after U.S. President Barack Obama said the legislation would be "a step backward for all Ugandans."

White House spokesman Jay Carney.

(SOUNDBITE) (English) WHITE HOUSE SPOKESPERSON JAY CARNEY SAYING:

"We are undertaking a review of its -- of our relationship with