Men have twice as many sexual partners as women over the course of their lives, research suggests。

The Health Survey for England found that men reported having 9.3 different partners on average, with a quarter of men boasting of more than 10 conquests。

However a third of those questioned admitted they were only estimating the number of notches on their bedposts。

By contrast, women had a mean average of 4.7 sexual partners in their lives so far, with a quarter having just one. They were more likely to be certain of the number of lovers they had had。

Among older women, monogamy was even more common with 40 percent of those aged between 55 and 69 saying they had only ever had one sexual partner。

Older women were also far less likely to be sexually active, with 36 percent saying they had not had a partner in the past year. Overall a fifth of respondents aged between 16 and 69 had been chaste。

The poll of 14,000 people, published by the NHS Information Centre on Thursday, suggested that younger generations were losing their virginity at ever earlier ages and taking more risks。

Its chief executive Tim Straughan said the annual report, which asked questions about sex for the first time, "paints a picture of sexual behaviour which is changing over the generations with younger women tending to begin having sex younger"。

A fifth of men and one in seven women said they had had sex before their sixteenth birthday, and the median age for first sex was 17. Overall fewer than one in 10 of those questioned were still virgins。

But among 16 to 24 year-old women the proportion who had lost their virginity before 16 – which would mean their partners were breaking the law – rose to 27 percent。

In addition, 15 percent of young women had had between two and four different sexual partners in the past year。

The Public Health Minister, Anne Milton, said: “Young people should think carefully before having sex - it's not something to rush into. Consider seriously if it's right for you, what contraception to use and the best way to protect yourself from sexually transmitted infections。”

調查顯示，英國男性一生中性伴侶的數(shù)量是女性的兩倍。

英格蘭健康調查發(fā)現(xiàn)，男性平均一生有9.3個性伴侶，四分之一的男性還有10個以上的性伴侶。

不過，三分之一的被調查者承認他們只能說出性伴侶的大概數(shù)目。

相比之下，女性平均一生有4.7個性伴侶，四分之一的女性只有一個性伴侶。她們對性伴侶的數(shù)量一般更確定。

在年齡較大的女性當中，一夫一妻制更普遍，55到69歲的女性有40%稱自己只有過一個性伴侶。

年齡較大的女性性活躍的可能性也低得多，36%的年長女性說自己在過去一年中一個性伴侶也沒有�？傮w上，16到69歲的受訪女性有五分之一一直保持貞潔。

英國國家醫(yī)療服務體系信息中心周四發(fā)布的這一調查涵蓋了1.4萬人，調查結果顯示年輕一代失貞時的年紀更小，而且冒的風險更大。

信息中心的執(zhí)行總監(jiān)蒂姆?斯特勞漢說，這一年度報告“描繪出幾代人性行為的變化，更年輕的女性通常更早發(fā)生初次性行為”。該調查首次詢問和性相關的問題。

五分之一的男性和七分之一的女性說他們在16歲生日前就有過性行為，而發(fā)生初次性行為的平均年齡為17歲�？傮w來看，不到十分之一的受訪者仍保持處子之身。

16到24歲的女性當中，在16歲前就失貞的比例升到了27%，這意味著她們的性伴侶也不到英國進行合法性行為的最低年齡線。

此外，15%的年輕女性在過去一年中有二到四個不同的性伴侶。

英國公共衛(wèi)生部部長安妮?米爾頓說：“年輕人應該在發(fā)生性行為之前先仔細地考慮一下——性行為并不是那種可以貿然進行的事情。認真地想想這么做是否適合自己，應采用什么樣的避孕手段，以及用何種最佳方式來保護自己不傳染上性傳播疾病。”