Men Who Smoke Lose Their Y Chromosome

Women have two X-chromosomes, whereas men have one X and one Y chromosome. So, it was very intriguing when scientists in Sweden found that male smokers are much more likely not to have a Y-chromosome in their blood than are non-smokers. The findings were published this week in Science and NBC News covered the story.

The team of Finnish researchers had already shown that men who are missing the Y chromosome from their red blood cells have a higher risk of cancer. They're not sure why. For the latest study, published in Science, they looked at blood samples from about 6,000 men taking part in other health studies and looked at their blood samples and lifestyle factors including age, blood pressure, diabetes and drinking.

The more the men smoked, the more likely they were to be missing the Y chromosome in blood cells. But men who had quit smoking seemed to get the Y chromosome back, they found.

I grew up in an era when the Marlboro Man was supposed to epitomize manliness. It turns out that smoking has exactly the opposite effect.