The practice of men drinking their partner's breast milk is to come under the microscope in a landmark study into the trend, which is growing in the African nation of Uganda.
The phenomenon is not uncommon in some areas of Uganda, and in parts of Kenya and Tanzania, reports Louise Hunt in an article for The Guardian.
There are concerns over the impact on babies' nutrition and its link to gender violence and coercive behaviour.
Now a study, by Kyambogo University in the Ugandan capital of Kampala and Britain's University of Kent, will examine the causes and results of adult men demanding breast milk from their partners.
The trend was largely hidden from public view until Uganda's minister of state for health, Sarah Opendi, spoke out in parliament in 2018.
She warned of "a growing culture of men demanding to suckle, which was becoming a problem for some breastfeeding mothers and their babies".
She went on to describe the reasons why many men claim they need the milk, saying "men are part of the problem during breastfeeding. A mother is breastfeeding, you also want something on the other side, saying that it can cure HIV/Aids, cancer, male dysfunction. It is a myth."
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As part of the study, anonymous interviews were carried out with four motorcycle taxi drivers in a rural district.
They told researchers that they had "never talked about it" but said it gave them energy.
"It sustains me, I come home for lunch and it relieves stress in the middle of the working day," said one.
Dr Peter Rukundo from Kyambogo University told Hunt that many men believed drinking breast milk could cure diseases such as Aids and cancer.
They also used it as a way of initiating sex, even with partners who had just given birth.
Another subject told researchers: "When breastfeeding, I feel like I'm being looked after like a child, and this becomes addictive. I feel like a prince."
Dr Rowena Merritt, a lead researcher on the project, said women were coerced into taking part.
One woman revealed to the study that she feared her husband would stray if she refused and a man admitted that women's refusal could cause violence because men "become obsessed".
Health professionals told researchers they knew of cases where babies had to be given formula because partners wanted the breast milk.
They also revealed women were presenting with infected or bitten nipples and detailed risks to babies because of cross-infection.
Rukundo told The Guardian that the Ugandan government had a role to play.
"We don't have any clear message or deliberate effort, despite the health minister saying the issue is there. So, in a way, it is denial. If they remain silent, the issue will remain underground," he said.