Sex may not always make the earth move, but there is evidence that it can shake up a woman's genes.

Scientists have found that a single sperm molecule has wide-ranging impacts on female fertility, immunity, behaviour, eating and sleep patterns. And although the effects were seen in fruit flies, the researchers believe many may occur in higher animals including humans.

The sperm peptide, a piece of a protein, triggered a complex pattern of changes in gene activity. These led to responses which became apparent at different times and in different parts of the female body.

Some appeared to advantage the male at the expense of the female. For instance, after mating the female became less receptive to other males, and invested a lot of energy into ensuring the survival of her offspring.

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  • Health Benefits Of Sex

    Besides being fun and pleasurable, sex also offers many health boosts many of us take for granted. Take a look at these surprise benefits of having regular sex...

  • Sex... Wards Off Illness

    According to research from <a href="http://www.wilkes.edu/pages/1.asp" target="_hplink">Wilkes University</a>, making love twice a week releases an antibody called immunoglobulin A or IgA, which helps protect the body from infections and illnesses. Other research suggests that frequent ejaculations in men reduces the risk of prostate cancer later in life. According to the <em><a href="http://www.bjui.org/default.aspx" target="_hplink">British Journal of Urology International</a></em>, men who ejaculate five or more times a week, had a lower risk of prostate cancer.

  • Sex... Burns Off Calories

    It doesn't take an expert to connect an energetic love making session with burning calories. Just thirty minutes of action under the sheets burns off around 85 calories. After 42 half-hour sessions, you could burn 3,570 calories, which is the equivalent of 1lb in weight. By having sex three times a week for a year, you could burn off the equivalent of 5lbs a year. Who needs a diet?!

  • Sex... Relieves Pain

    During sex, a hormone called oxytocin is released when the body climaxes, which increases the level of endorphins that acts like natural a pain relief. This causes the body to relax. Many notice their aches and pains, like swelling, inflammation, headaches and menstrual cramps, disappear after sex and gradually improve with regular action.

  • Sex... Helps Beat Depression

    Women who have regular orgasms are generally more relaxed, less depressed and mentally, physically and emotionally satisfied. Regular sex also helps the body sleep better as it relieves tension plus it helps the brain produce serotonin - the chemical that gives the body a 'mood' lift and is commonly found in antidepressants.

  • Sex.. Keeps You Young

    Regular sex releases a surge of plethora chemicals into the body, also known as the 'happy hormones', and they contain testosterone. As we age, the level of testosterone decreases, so the more sex you have, the more your hormone levels increases. This surge of hormone help keep bones and muscles healthy - plus it keeps skin looking plump and youthful. In women, regular sex also helps keep the pelvic floor muscles healthy, which decreases the chances of not-so-sexy incontinence later in life.

Lead scientist Professor Tracey Chapman, from the University of East Anglia, said: "We tested the effects of one enigmatic seminal fluid protein, known as the 'sex peptide', and found it to change the expression of a remarkable array of many genes in females - both across time and in different parts of the body.

"There were significant alterations to genes linked to egg development, early embryogenesis, immunity, nutrient sensing, behaviour and, unexpectedly, phototransduction - or the pathways by which they see.

"It showed that the semen protein is a 'master regulator' - which ultimately means that males effectively have a direct and global influence on the behaviour and reproductive system of the female. Such effects may well occur across many species. The bottom line is that it's possible these sorts of processes could occur in humans.

"We don't know much about it yet, but over the last few years a number of people working in this area have been looking at interactions between human sperm and what happens in the female reproductive tract. It's well known that a lot of changes occur following mating, but I think it's true that they could be more far-reaching than anyone has imagined."

Effects on immune system genes may help prevent infection of the reproductive tract, or even act as a barrier against sperm from a different male, she said.

See also:

Women's ‘Sexiest Time' Revealed In Sex Survey

Women's Sexual Fantasies - The Latest Scientific Research

Study Reveals That Women Over 30 Are More Likely To Have Sex After First Date

The research is published in the journal Proceedings of the Royal Society B.

One of the behavioural changes seen involved female flies being driven to eat more - and more selectively - in preparation for egg laying.

But the responses triggered by sperm proteins were highly costly to the female, even to the extent of shortening lifespan, the research suggested.

"There can be a tug-of-war, where males employ semen proteins to ensure that females make a large investment in the current brood, even if that doesn't suit the longer term interests of females," said Prof Chapman.

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  • Ready, Steady, Oooh!

    Do you want to <em>really</em> get into the spirit of the London 2012 Games? Get busy under the sheets with these Olympic-inspired sex positions that are guaranteed to pass the time during the boring bits. Tips provided by <strong>Emily Dubberley</strong>, author of upcoming book, <a href="http://www.amazon.co.uk/Acrobatic-Sex-Positions-Moves-Crazy/dp/1592335373" target="_hplink"><em><strong>Acrobatic Sex Positions</strong></em></a>, available in December. Emily is also founder of erotic blog, <a href="http://www.cliterati.co.uk/" target="_hplink"><em>Cliterati</em></a>.

  • The Skier

    <strong>How To:</strong> The man lies on the bed with his buttocks at the edge of the bed, legs in the air. The woman starts by lying on top of the man with her back against his chest and pelvis above his, then slides onto him. She should then gradually sit up and lean forward, taking it slowly to ensure she doesn't bend her man the wrong way. Once the woman is sitting up, she should slowly lower her legs onto the floor then rock back and forth as desired. The man should keep his legs raised throughout (thus allowing easy access for the woman to reach between her own legs to stroke his penis and balls) though he can rest them against the woman's back if this proves too hard on his thighs. <strong>Acrobatic tip:</strong> The woman should use her love muscles to raise herself, Pilates style, when starting this position. Not only will it make things easier, but it'll tighten everything up, too.

  • The Diver

    <strong>How To</strong>: The woman lies on her back on the bed with her hips aligned with the edge of the bed and legs splayed. The man then does a handstand at the side of the bed, with his body angled toward the bed to allow him to slide inside her. The woman controls the thrusts by flexing her pelvic floor muscles and arching her hips off the bed. <strong>Acrobatic Tip:</strong> If the man is über-fit, he can control his thrusts by pumping his arms push-up style. This is not for the faint-hearted!

  • The Skewered Hurdler

    <strong>How To:</strong> The guy lies back leaning against a sofa or bed for support. The woman then straddles him sideways splits-style, resting her hands on the floor to allow her to control her bouncing. The man can assist by putting his hands on her hips to help her move up and down should she start to tire. <strong>Acrobatic Tip: </strong> The seriously bendy babe can try leaning all the way forward to rest her head against her ankle, thus giving constant clitoral contact against the guy's upper thigh. If the guy's as limber as the woman, he can also do the splits, thus allowing easy access to his balls and bottom. Male G-spot stimulation, you say? That'll do nicely.

  • The Kiss-Up

    <strong>How To:</strong> Lie on the bed missionary style, with the man on top of the woman and his weight supported on his hands. He should then start doing press ups, letting his lips meet his lover's every time their faces meet. Once he is feeling suitably warmed up, swap positions so that the woman is on top and has to do press ups to kiss her man. <strong>Acrobatic Tip:</strong> When you're both feeling as if your upper body is primed and ready for action, it's time to put your lower half through its paces.

  • The Weightlifter

    <strong>How To:</strong> The woman wraps her legs around the man's waist and slides onto him. The man puts his arms around her waist, and the woman slowly relaxes her body entirely, leaving the man to totally support her weight and move her body as he desires. <strong>Acrobatic Tip:</strong> The woman can raise one or both legs to rest against the man's shoulders to deepen penetration - but don't even think of trying this unless the man is very strong indeed, and the woman has a toned pelvic floor.

  • The Deep Bender

    <strong>How To:</strong> The woman lies on the bed with her head hanging over the side. The man then straddles her face and slides inside her mouth, then squats down to touch his fingers to the floor and enjoy deep throat into the bargain. <strong>Acrobatic Tip:</strong> The woman can put her hands on the man's hips to control the pace and help avoidgagging. However, by hanging her head backwards, she'll lengthen her throat which should minimise the risk.

  • The Bow and Arrow

    <strong>How To:</strong> It's time for spreading those thighs wide once more, but this time the woman can use her hands to help her maintain the position. She simply lies on the floor or bed with her legs spread as widely as possible and hands gripping her ankles. Talk about an open invitation for the guy to kneel between her thighs and start thrusting! Caressing the thighs as he thrusts will add extra-sensual pleasure for the woman. <strong>Acrobatic Tip:</strong> For a real challenge, the guy can spread his thighs equally wide and lean forward to kiss his lover. Yep, it's a stretch, but the clitoral stimulation it provides will make his partner's squeals all the reward that he needs.