A university lecturer is suing his ex-wife for £83,500 after she allegedly swapped his sperm for an ex-lover’s while undergoing fertility treatment.

The respected academic claims he was led to believe that he was the father of a child born through in vitro fertilisation (IVF). He subsequently paid thousands of pounds in child maintenance after he and his wife divorced. A DNA test eventually revealed the child was not his.

In the first case of paternity fraud involving IVF in the UK, the lecturer claims that when his former wife travelled to a fertility clinic in Spain with her ex-lover – a visit his ex-wife admits took place – the ex-lover pretended he was her husband and donated sperm .

A university lecturer is suing his ex-wife for £83,500 after she allegedly swapped his sperm for an ex-lover’s while undergoing IVF (file picture)

The case will come to the High Court this week, with the parties referred to by pseudonyms. The Mail on Sunday knows their identities but they cannot be named for legal reasons.

The couple married in 2002, and the husband – who already had two children by a previous marriage – had his vasectomy reversed so they could have a baby. But the wife failed to conceive and turned to the ex-lover for comfort.

A family source said: ‘The marriage was turbulent. His wife got bored with her husband and had long conversations with her ex-lover.’

In 2004 the husband and wife visited the IVF clinic where the lecturer provided sperm for use later. But the following year, his wife returned with her ex-lover and he donated sperm.

During a third visit, she had a fertilised egg implanted with the clinic using her ex-lover’s sperm.

Seven months after the baby’s birth, the husband and wife separated and were divorced in 2007, with the lecturer sharing custody of his son, now aged nine.

The 60-year-old academic has launched a High Court (pictured) action in a bid to get £83,500 damages, including the return of child maintenance payments

As the child grew older, the academic noticed he looked like his wife’s ex-lover. A DNA test carried out when the boy was five confirmed he was not the lecturer’s son.

His wife, now aged 53, said there must have been a mix-up with his sperm at the fertility clinic, but denied intentionally deceiving her ex-husband. But by then the lecturer had already paid thousands of pounds in maintenance.

Now the 60-year-old academic has launched a High Court action in a bid to get the money back. His claim for £83,500 damages in the Queen’s Bench Division is for fraudulent misrepresentation and the return of maintenance payments, plus interest.

Professor Allan Pacey, a fertility expert at the University of Sheffield, said: ‘It’s extremely unlikely the clinic mixed up the sperm. It’s a bizarre case.’