John Pickett - thought to be the first man to have had two "late failure" vasectomies - said he was "stunned and diappointed" after losing the case at Leeds High Court and having costs awarded against him. The costs are expected to amount to tens of thousands of pounds.
In a three-day hearing, Mr Pickett, 47, and his wife, Pauline, 41, said surgeons at St James's Hospital, Leeds, did not tell them there was a "remote" risk of the second vasectomy, carried out in 1992, failing. They opted for the second vasectomy after the first, in 1988, failed and Mrs Pickett gave birth to a daughter.
The couple, of Roundhay, Leeds, told the court that if they had realised there was still a risk of pregnancy they would have used additional contraception after the second operation.
Judge John Altman said that although he found the hospital had breached its duty of care by not giving them proper advice before the second vasectomy, it would not have made any difference. "They knew of the risk, they had been through it before and the reality is that it was not so much a matter of medical risks and probability which coloured their judgment as to what to do in relation to alternative contraceptive measures. It was a human decision that in effect it couldn't happen to them twice," he said. "It is quite clear to me that is what in the end reassured them to proceed."
He added: "There was a negligence act, but I also find that that negligence act made no difference whatsoever, either to their state of mind or their state of knowledge at the time."
The couple have six children, aged between four and 14, one of whom was adopted just before Mrs Pickett discovered she was pregnant after the first vasectomy.
She gave birth to a daughter, Louise-Charlotte, now seven, three years after the first operation and Emily, four, two years after the second vasectomy.
The court heard that the chance of late failure, where the patient becomes fertile after being given the all-clear in the months after surgery, was one in 2,000-3,000.
However, medical experts said there was no record of two late failures occurring anywhere in the world. Outside court, the couple said that although they were disappointed they were also relieved that the proceedings, which began four years ago, were finally over. Mr Pickett, an engineer, said: "We went in believing that we had a good case, otherwise we would not have gone to trial.
"Although it was in the back of our minds, we are disappointed that costs were awarded, having proved there was a breach of duty of care.
"I think what it has shown is that doctors have a duty of care above just doing the operation. This has always been our concern - the fact that nobody seemed to be bothered."