The private lives of people who like to pretend to be babies is to be revealed in a Channel 4 documentary.
15 Stone Babies shows how adults dress up as infants and want to be cared for as if they were a newborn - having their nappies changed, being bottle-fed and sucking dummies.
One of the men featured in the film explains that there are between 200,000 and 500,000 "adult babies" in the US and UK alone and that social media is making it easier for them to connect.
The adult babies in the documentary explain that the practice is not perverse or paedophilic, but is about reverting back to innocence. It also looks at the 'mummies and daddies' who care for their adult babies.
Derek, an adult baby in the documentary, said: "When I put a nappy on it takes me back to that time when I had no stress. It's a special bond between two people.
"As soon as you mention adult babies, they all think it's something to do with children and paedophiles. We don't want to be with children, we want to be the child."
His wife added: "I think in most wives, there is a bit of a mother bond with the husband."
The practice of dressing and acting like a baby is known as paraphilic infantilism but there is little in the way of formal research on the subject, although some have linked it to masochism.
People who have a particular fetish for nappies are known as diaper lovers, and wearing a nappy is sexually arousing. People who just enjoy being treated like a baby, but do not see it as a fetish, are adult babies.
Many of those featured say they want to rid themselves of their daily responsibilities to relax, and dressing like a baby allows them to escape the pressure of adulthood.
A female adult baby shows the filmmaker around her playroom, as her 'father' says: "I'm just going to get her changed real fast."
She is asked how old she is, to which she replies: "I don't know, daddy might know."
Others, however, do not embrace their desire to become as a baby: One man says: "I just think I'm weird and a freak, and [people will] never want to talk to me again."
Another added: "I can't tell her how I feel."
15 Stone Babies, made by Minnow Films, is on Channel 4 at 10pm tonight (Thursday).