Science of Sex

Scientists are now conducting new experiments to decipher more and more of the coded signals our bodies send out to attract a partner. At the University of New Mexico, researchers believe that our nose interprets signals in mere milliseconds without us being aware that we're doing it. They got athletes to exercise and then gave their sweaty shirts to female biology students to sniff. What they smelt were the men's pheromones: airborne molecules exuded from their sweat glands. The women had no idea which shirt belonged to which athlete. They discovered that the female students preferred the smell of men that had a major histocompatibility complex, or MHC, that was different from their own. This group of genes plays an important role in the body's defence system, and favouring guys whose immune system is unlike their own makes good evolutionary sense.

But our noses can detect more than just different genes: they can also detect symmetry. It may seem bizarre, but women prefer the smell of men who are more symmetrical. The fact that symmetry attracts the opposite sex is nothing new, it was first noted by researchers in the 1990s. In the study, women selected pictures of men they found most attractive. When they analysed blood from the men they chose as the most attractive they found a greater variety of genes, and hence a stronger immune system. But no one quite knows how our faces convey this information.

Lust can often lead to romance and then love….

Love causes a lot of activity in the caudate area of the brain where there is a dense area of dopamine receptors.

We don't just mate with anyone. Usually our brain makes us focus our attention on just one individual. What fuels this passion for one person is romantic love - that feeling of ecstasy so potent it should carry a health warning. Romantic love is not a fanciful notion - it's scientifically measurable. If you've ever been in love, you know what an overpowering emotion it can be.

Scientists have analysed the blood flow through the brains of students who are self-confessedly deeply in love and what they discovered was that being in love affects the brain in much the same way as using certain illegal stimulant drugs! The brain areas concerned have a high concentration of receptors for the hormone dopamine. Dopamine is a neurotransmitter that is involved in the control of fine motor co-ordination, short-term memory and emotions such as sexual desire. It is one of the body's 'feel good' chemicals. Elevated levels of dopamine produce extremely focused attention and unwavering motivation, the very characteristics of romantic love. Heightened dopamine levels explain why love stricken men and women become so dependent on their relationship and why they crave to be with their partner - at least long enough to get the female pregnant. Sexual bonding leads to repeated copulation and that leads to offspring. The desire to fall in love seems to be a basic human need across all cultures. In fact, love is even more powerful than sex: some people commit suicide or commit murders when they are rejected in love. Romantic love remains a universal experience deeply woven into the fabric of the human brain.