الجمعة، 15 يوليو 2016

Able semen: sperm has a shelf life too (even if Mick Jagger is still going strong)

The rapid decline in women’s fertility as they age is well known – but what about men and their sperm? Read the fine print and the answer becomes less clear

Some weeks ago, a sperm cell (let’s call this little guy Vince) fused with an egg and resulted in a pregnancy. What makes Vince a newsworthy sperm cell is that he came from a 72-year-old penis. And not just any old 72-year-old penis, but the one attached to Mick Jagger, frontman of the Rolling Stones.

I suspect that, like me, women the world over are frowning at their screens as they hear news of heroic lil’ Vince and the 29-year-old ballerina he impregnated. Because if this headline were about Cher getting ready for a fresh round of diapers, the reaction would range from disbelief to disgust – and Cher is two years younger than Mick.

A woman’s best reproductive years are in her 20s. Fertility gradually declines in the 30s, particularly after age 35. Each month that she tries, a healthy, fertile 30-year-old woman has a 20% chance of getting pregnant … By age 40, a woman’s chance is less than 5% per cycle, so fewer than 5 out of every 100 women are expected to be successful each month.

Unlike the early fertility decline seen in women, a man’s decrease in sperm characteristics occurs much later. Sperm quality deteriorates somewhat as men get older, but it generally does not become a problem before a man is in his 60s.

About 77% of sperm are viable. But this sketch also shows what happens when an average man comes - each one of these little guys represents a million sperm. A typical ejaculation is 2.8ml and each ml contains 48 million sperm. Source: Semen analysis, Journal of Fertility and Sterility, June 1974 #datasketch #sperm

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from Pregnancy | The Guardian http://ift.tt/29I4Nz7

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