HIV-positive couples are being paired up for marriage by a northern Nigerian state in an attempt to reduce the spread of the disease.
But international Aids experts have voiced concern at the plan.
Warren Naamara from UNAids said the two people could have different strains of the virus, which could interact. He said the couples should use condoms.
Around 70 couples have been matched up in the last few weeks, Bauchi state authorities told the BBC.
Authorities in the state say they are trying to stop HIV spreading and battle the "isolation and stigma" of the disease.
Some 3% of Nigeria's adult population - 2.4 million people - is estimated to be HIV-positive
Bauchi State operates under Sharia, or Islamic laws, and the use of condoms is not encouraged.
Dr Lirwan Mohammed, the executive secretary of the Bauchi Action Committee on Aids, said the polygamous culture of northern Nigeria had increased the spread of the disease.
Authorities say the move would stop the spread of HIV
"Polygamy, as we have discovered, has become a potent source of spreading the HIV scourge in Nigeria," he said.
The marriages were arranged under strict confidentiality, he said.
"Suitors who have tested positive and are willing to wed each other, can reduce the spread of the virus and also cushion the psychological trauma of isolation."
Couples are introduced to each other during counselling sessions and are free to say yes or no to each potential partner, says the BBC's Shehu Saulawa.
One groom, speaking to the BBC's Hausa service on condition of anonymity, said he was confident the plan would combat the spread of Aids in Nigeria.
"If we should fear God, we should stop spreading the HIV virus through indiscriminate marriage, thereby infecting innocent people," he said.
"Marrying someone with the same HIV status will reduce the spread of the scourge."
But the head of the United Nations agency in charge of battling the disease in the country said the scheme was dangerous.
"There may be a very big danger in terms of the spread of the disease," said Mr Naamara
He also said it was "not advisable" for such couples to have children.
"The chances are that child would become a double orphan, they would lose both parents."
"Our advice is they should use condoms."
Last month Bauchi state reportedly locked up sex workers who had tested positive for HIV.