Breast might be best for baby, but experts are warning that the growing trade in human breast milk poses serious health dangers to consumers.
Bodybuilders, cancer patients and fetishists are amongst adults buying excess expressed milk from mothers, via specialist online sites and social media groups.
Researchers at the Queen Mary University of London tested breastmilk for sale online and found that 93% of samples contained bacteria, and warned that non-sterile equipment is being used to express and store the unpasteurised milk. Threats include hepatitis B and C, HIV and syphilis.
Breastmilk - often referred to as "liquid gold" – is bought for its supposed health benefits, by fetishists and even some "foodies".
However, claims that the milk boosts the immune system are misleading and could be dangerous to cancer patients, warned study author Dr Sarah Steele, from Barts and the London School of Medicine and Dentistry.
"For cancer patients and other immuno-compromised people, the immune system is not functioning the same as in a healthy adult," she said.
"It is advertised with an immune benefit, but actually it poses real risks, and you're exposing yourself to bacteria and viruses that could complicate the medical condition in a dangerous way."