WOMEN AND MEN He calls her bunnikins, she calls him stinkipoo: what makes grown-up couples behave like children?
the day that Mark Shinton's girlfriend called him "Katkin Noodlepants" in front of his mates was possibly the most embarrassing day of his life. "It destroyed me," he shudders. "My mates call me 'Katkin' to this day." And there's worse: "In bed she'd talk to my penis in baby talk, which to me implied that she thought it wasn't up to the adult job it was designed for. She used to call it 'Pe-pe'. I thought it was a bit sick but I had to play along or she'd get really hacked off and I wouldn't get my evil way."

Katkin has since terminated the relationship. Yet, poor dear, what makes him so special? Most couples engage in some form of baby talk - even if merely a cooing tone when speaking to their Furry-Bunny-Tummy, sorry, partner, on the phone. Women are the main culprits; according to men, that is. Katkin, 28, derides such patter as "a substitute for intelligent conversation". Tom Rodgers - 31 and quite grown up - is equally disdainful of his fiancee's toddler talk. He says: "I hate it. It's manipulative and demeaning. It puts our relationship on a false footing. It's emasculating. I'm trying to pretend I'm a real man yet here I am speaking in psycho- baby-babble."

Judging from this spew of bile, the strain of a double life has got to him. Tom adds: "It's a mind game of the lowest order. I think it's linked to her menstrual cycle. I'm keeping records."

Having vented spleen, Tom (aka Tommie-Sweetie) tries to be charitable. He admits: "There's an element in men where they need to be mothered and that's the short cut to it. It's a regression back to childhood days. It's like how your mother spoke to you when you were a kid."

But Maria Blakely, Tom's intended, sees it differently. She says: "I talk baby talk to Tom when I want to be a little girl. That's usually when I want him to take care of something which I don't want to do, like make dinner or clean the flat when I'm tired. It's either baby talk or bossiness." So Tom's verdict of "manipulative" wasn't so much slanderous as totally accurate? Maria objects: "Sometimes you feel like you're getting closer to someone when you talk that way, by going back to childhood. It's wanting to be looked after and to not take responsibility for things."

Maria may speak to Tom as if they were both five years old, but she's a smart woman. Psychologist Susan Marchant-Haycox says: "All of us do it, even if we're not aware of it. A girlfriend of mine was listening to me talk on the phone to the man who was my first steady boyfriend, and she said, 'your voice completely changes!' People probably do it because they're reverting back to childhood. It's going back to an era where you felt quite safe. Men also engage in baby-talk to a lesser extent - probably for the same reason that women can cry but men can't - if a man cries openly in public then he's seen as an emotional wimp, but if a woman does it's perfectly acceptable."

Stereotypically then, men contacted for this article were coy. One 37- year-old was indignant: "Why did you think of me? How dare you!" Because rumour has it that a squad of cuddly toys share your marital bed. "There are only two, and one doesn't have a name. There's only Florence. And it hasn't led to any other problems." So no cutesy language or pet names between you and the missus? "Yes, but I couldn't possibly tell you. I'd have to tell you the reason why and ... no, no."

Another snapped: "When my girlfriend talks to me in baby talk I think either she's done something wrong or she wants something. She's like a little dog who's pooped in the house or who wants to be let out to have a poop. I don't do it. I think it's fawning and doting and subservient."

In fact, those who adhere strictly to the Queen's English when conversing with their partner, even at the most Andrex puppy of moments, are the weirdos. The experts say it's normal to refer to a mature adult as "Katkin", say. Ms Marchant-Haycox explains: "Often basic patterns of parent-child behaviour carry over into courtship. Baby talk, sucking, kissing, biting, hand-clutching, embracing, are all suggestive of parent-child contact and can be seen as a return to parent-infant style of tenderness and caring. Humans are usually dependent on their parents until they're ready for mating, so it's natural that the instinct is displayed during adolescent and adult courtship behaviour."

But the context has to be right. In other words, we act like adults until our special relationship becomes intimate. Then we start behaving like X-rated Andy Pandys and Looby-Lous. The maternal instinct has a lot to answer for, and baby talk is part of this package. Some (masochistic) women are attracted to the boyish aspects of their partners - marvelling to friends how he gets so excited about football, and he's hopeless at clearing up after himself, isn't he sweet? The same women tend to exacerbate this sorry state of affairs with grooming behaviour - picking hairs off his jacket or wiping a bit of stray food off his lips.

But men, it turns out, are equally culpable. Ms Marchant-Haycox says this role-play "can be highly arousing for both partners". Blokes, she says, are seduced by women "who convey infant-type signals like big innocent eyes and soft skin". Even so, some men take the youth-equals-fertility theory a tad too far ...

As for the paternal instinct - it gives rise to habits which, frankly, he wouldn't want on his CV. Ms Marchant-Haycox says: "A man may cradle his lover in big arms and indulge in baby talk as if to reassure her that he's there to protect her from the big bad world. The powerfulness of his body may make her feel vulnerable yet protected ... and both may find the whole exercise highly sexually arousing."

This sickly revelation is borne out by Mr Dog-Poop's girlfriend. While refusing to coochy-coo, DP acts like a toddler when it suits him. She reveals: "Last week he tipped a cup of tea over my carpet and chipped my favourite china mug. He stuck out his lower lip, covered his face with his hands, and giggled. I couldn't shout at him. I felt like his mummy. And when he's drunk he's childlike. Last night he reeled home from a cricket do clutching a toy fishing net so he could 'catch crabs', and he forced me to sing a football song with him and shouted when I got the words wrong. He was so irritating I wanted to hit him, but in the right sort of measure I do find his boyishness sexy."

Anyone squirming with horror and/or alarm at this admission can take comfort in the fact that Ms Dog-Poop's fetish does not apply to every member of the female sex. Feminist and Cambridge university lecturer Gillian Beer laughs at the very suggestion that she - or indeed any of her friends - might be guilty of such a toe-curling crime. "I've no idea whether my acquaintances do this with their partners," she says. "I can't say it's something that's part of my experience. I can only believe that people behave like this when I see those extraordinary St Valentine's Day cards. They are my only access to it, and I'm baffled by it.

"I once holidayed with an older couple who were like that, and I found it rather cloying. I thought 'ugh', but maybe that's because I wasn't part of it. It's not a spectator sport."

Not wishing to seem ungracious, Professor Beer adds: "Maybe all of my friends are doing it. Presumably we all have our own ways of sexual expression. If it were the case that only women were doing it, then I'd say it was self-diminishing, but as it's something that people do in the privacy of their own homes, I really think it's up to them."

This is the bottom line. If people wish to imitate Munchkins as part of their seduction routine "den dey should go wight'' ahead. The habit is perfectly normal and nothing to be ashamed of. However, they should take care not to inflict their choochywoochyness on any third party, because he or she is likely to feel left out.

They should also remember that occasionally it's a real joy to communicate with your partner on an adult level. After all, there's a time in most relationships where you wish to borrow a vast sum of money/be collected at 1am from a distant railway station/issue a stinging reprimand for an outrageous misdemeanour. At such moments it's best to employ your most impressive and intimidating command of the English language. Aping a toddler may be cute, but sometimes there is no substitute for peer pressure.