A man has admitted having sex with four of the five women he is accused of murdering, Ipswich Crown Court heard.
Steve Wright's DNA was found on the bodies of three of the women, who had all been working as prostitutes in Ipswich to fund drug habits.
Prosecutors said the chance the DNA was not the defendant's was "one in a billion" and was evidence of his guilt.
Timothy Langdale QC, defending, said Mr Wright did not dispute the scientific findings, but denies he is a killer.
He told the jury that Mr Wright, from Ipswich, was someone who used prostitutes in the town and that was how he came into contact with the five women.
Anneli Alderton, 24, Paula Clennell, 24, Annette Nicholls, 29, Tania Nicol, 19, and 25-year-old Gemma Adams went missing during six weeks in 2006.
All five bodies were found naked and dumped in remote areas of Suffolk between 2 and 12 December.
The women were all found dead on the outskirts of Ipswich
DNA matching the defendant was found on the bodies of Miss Alderton, Miss Clennell and Miss Nicholls.
Mr Langdale told the jury they had to consider the world in which the women operated, and the people associated with them.
He said the defendant had sex with four of the five women and had picked up Miss Nicol with a view to having sex with her, but changed his mind and dropped her off.
He said this explained the DNA link between Mr Wright and some of the victims
"It's therefore not the case that the defence are suggesting some kind of freak coincidence," said Mr Langdale.
"You will have to consider the evidence, for example, from the scientists as to the real possibility of someone being able to kill the victims without leaving any trace on the bodies of the victims."
Earlier, Peter Wright QC, prosecuting, outlined the case against Steve Wright.
He told jurors the forensic evidence of links between the defendant and the women's bodies painted a "compelling picture of his guilt".
The jury was told semen-stained gloves, which contained DNA samples that could have come from Miss Nicholls and Miss Alderton, were seized from the defendant's car.
Mr Wright said it would be "highly unusual to say the least" for the defendant to be wearing the gloves while having consensual sex with the two women.
There was also evidence fibres had been transferred between the bodies and the defendant's sofa, jacket, lumberjack coat and three pairs of trousers, he told the court.
Mr Wright told the jury the DNA and forensic findings did not point to an "unfortunate coincidence" but rather that the defendant was "engaged in an active campaign of murder".
The trial, which is expected to last six weeks, has been adjourned until Monday.