One billion and four... one billion and five...

Sperm count angst? Go to jail and don't eat the fish, advises Gary Andrew Poole

There was a time when British men rarely contemplated the liquid stored in their testicles. Those days are over. The age of sperm awareness has dawned. It's difficult to open a newspaper without reading yet another report about falling sperm counts. But it's not too late to make sure you have heirs. Sure, we're living in a sperm-killing world, but there are ways to increase your count.

The good news is that sperm regenerate every 80 days. So sperm ejaculated last night were made two-and-a-half months ago. Unlike women's reproductive cycles, men can have children into their golden years. But some physicians warn that sperm get weary as we get older.

Obviously men can't alter old age but they can stop sperm abuse, so it's time to start, like right now, getting your sperm on an exercise regime and a healthy diet. Things to avoid:

Drugs. Steroid-takers, for example, might have Mr Universe bodies, but they have wimpy sperm.

Water from a tap because of lead poisoning.

Working as a field worker in a sugar cane forest. Herbicides kill sperm.

Soaking in hot baths. Sperm like to be about two degrees cooler than the temperature outside the body.

Working in indoor car-parking facilities; lead-laden petrol fumes eat sperm for breakfast.

The saliva-as-lubricant shortcut. Spit has been shown to harm motility.

Living in Thailand, Nigeria and Libya where men have unbelievably low sperm counts.

Increasing sperm count is much trickier. But research tells us that there are things that men can do to pump up the sperm volume, like:

Living in New York. Men in New York usually have higher than normal sperm counts.

Taking vitamins A, C, and E. Semen needs to be rich in oxidants.

Getting incarcerated. According to some researchers, prisoners usually have high sperm counts. Scientists speculate that the high sperm counts comes from the strict regime of prison life, thus less stress.

However, taking the prison route is a sketchy and unpleasant idea, and everyone who has attended a sex education class knows you only need one sperm to cause a pregnancy. Don't get too caught up in the numbers game. "Say you have a billion sperm. If they're not motile and healthy, it doesn't matter," says Dr Larry L Lipshultz, who directs male infertility research at Baylor College of Medicine in Houston.

Naturally, diet has an important part to play. Ralph C Dougherty, a Florida State University chemistry professor, is famous in sperm circles for publishing studies in the late 1970s linking low sperm counts to toxic chemical exposure. He has this advice:

"Eat a vegetarian diet that's high in complex proteins. Don't eat fish. Eat low on the food chain where food is bio-concentrated. Plants are good. As you get higher on the food chain - beef, fish - you're more likely to be exposed to chemicals. And beef is better than fish: fish live in water. I've found too many bad chemicals in fish to feel comfortable eating it ... bye-bye sperm!"