"CAIRO, Aug. 11 (Reuters) - The most prestigious institution of Islamic learning spoke out today against a United Nations draft document on population, saying the paper condones extramarital sex and unrestricted access to abortion.

The institution, the Azhar mosque university, set up in Cairo in the 10th century, says the document also undermines parental authority and might encourage prostitution.

In a statement, the center said parts of the document needed to be changed to conform with Islamic principles. The draft, prepared for a United Nations conference in Cairo next month, covers abortion, women's rights, family structure and adolescent sexuality, among other issues.

The Vatican is also campaigning against parts of the document, saying ambiguous language will promote abortion and artificial contraception.

The Azhar statement also criticized what it called ambiguities. The document "aims to defend sexual relations between members of the same sex or between different sexes outside legal marriage," the center said,