By Ania Lichtarowicz BBC health correspondent

Many practitioners have no medical qualifications

Female genital mutilation is still commonplace in Sudan, despite it being illegal, a new study has found.

A survey of university students, published in the medical journal Sexually Transmitted Infections, also revealed that three-quarters of men would prefer their wife not to be circumcised. This casts doubt on the traditional argument that circumcision increases a girl's chances of marriage.

The practice of female genital mutilation carries a maximum five-year jail sentence or fine in Sudan.

The procedure entails the removal of varying amounts of tissue from the genitalia, including all or part of the clitoris.

Although practised worldwide, it is most common in Africa, where it is performed on girls as young as three by people with no medical qualifications, and often without anaesthetic.

If a girl survives the procedure, she then faces many long-term medical problems, including major complications during childbirth.

Khartoum study

In a survey of more than 400 students at the University of Khartoum, 57% of female respondents were themselves circumcised.

Study findings 57% of women circumcised 80% of men and women oppose procedure 75% of men prefer uncircumcised wife 40% of respondents unaware procedure is banned

Most felt their mother had been responsible for the procedure.

More than 80% of men and women were against the procedure, and three-quarters of men said they preferred non-circumcised women, which contradicts the popular argument that uncircumcised women are unlikely to marry.

And at least 40% of students surveyed were also unaware that the procedure is illegal.

The rate of female genital mutilation remains so high despite its illegality because of confusing religious messages and ambiguous law, say the study's authors.