A Sleaford man who made a 14-year-old schoolgirl pregnant was jailed for 30 months at Lincoln Crown Court.
Edward Parker, 24, began a relationship with the girl just days after his partner gave birth to their child.
Phil Howes, prosecuting, said: "These were three instances of intercourse with a 14-year-old in his parents' car.
"He had taken the girl out for a car ride."
Mr Howes said Parker knew the girl's age and the illicit relationship was not suspected by others.
"All matters came out in the open in February 2012 when the girl made a visit to her doctor with stomach pain.
"It was discovered she was 11 or 12 weeks pregnant.
"She stated that the father was the defendant."
She later gave birth to a baby and a paternity test confirmed Parker as the dad.
The girl later told police that "he made a move and I just let him".
Mr Howes said that when police interviewed Parker he confessed saying: "The plan wasn't to get her pregnant.
"One thing led to another. I'm up the creek without a paddle".
Parker, of Jubilee Grove, Sleaford, admitted two charges of sexual activity with a child which related to three instances of sexual intercourse between July 2011 and February 2012.
He was jailed for 30 months, placed on the sex offenders' register for life and banned from working with children.
Judge Michael Heath told him: "This girl trusted you and cared for you but for you it was just sex.
"There is only one sentence that I can impose and that is an immediate custodial sentence."
Michael Cranmer-Brown, defending, said Parker bitterly regretted the relationship and lost his job over the incident.
"This has been a salutary lesson to him," he told the court.
"This was a one-off. This is not some predatory paedophile who targeted young girls."