A new law that would make chemical castration mandatory for sex offenders who rape children under age 15 or close relatives, cleared its first hurdle in Poland Friday.

Under the law, approved overwhelmingly by the Polish parliament's lower house, people convicted of raping under-15s would be obliged to take drugs intended to control their sexual urges — a practice known as chemical castration.

The law also raises the maximum prison term for the rape of under-15s to 15 years from 12.

The centre-right government proposed the bill in response to a series of cases in which fathers had sexually abused their daughters.

In cases where children aged 15 to 18 are raped, courts would decide whether the offender should undergo chemical treatment.

The law also would apply to people who rape close relatives, though the term was not specifically defined, nor was the age threshold in such cases.

Poland already offers the procedure on a voluntary basis. The bill still needs approval from the upper house of parliament and President Lech Kaczynski. Both are expected to support it.

With files from The Associated Press