A St. Louis teen confessed to raping his 11-year-old relative about 100 times after she gave birth to his baby in a bathtub, according to a news report.

Cops were tipped off to the alleged abuse at the hands of Norvin Leonidas Lopez-Cante when his father brought an infant to St. Joseph Hospital on Tuesday and told police someone left the child on his front porch, KSDK-TV reported.

The baby still had its umbilical cord and placenta attached and a body temperature of 90 degrees, the NBC affiliate said.

On Thursday, police visited the father, Francisco Javier Gonzalez-Lopez, and he told them his 17-year-old son was the father of the child and their 11-year-old relative was the baby’s mother — but claimed he had no knowledge of the abuse or the pregnancy until the girl gave birth.

Lopez-Cante later admitted to authorities that he had sex with the girl about twice a week, a total of about 100 times, the report said.

Cops arrested both the father and the son, KSDK-TV reported.

Lopez-Cante was charged with first-degree statutory rape, sodomy and incest.

Gonzalez-Lopez was charged with endangering the welfare of a child. Court papers show he was in the country illegally and was previously deported.