Male sex drive 'affected by oestrogen levels'
A female hormone can play an important role in determining male sex drives, new research has shown.
Published in the New England Journal of Medicine, the study revealed it is not just testosterone - the male sex hormone - that makes men keen to get it on with their partner.
The findings may impact how many condoms middle-aged men are required to buy, as it was discovered that oestrogen affects guys of this age more than has previously been thought - especially when it comes to declining testosterone levels and expanding waistlines.
Dr Joel Finkelstein of Massachusetts General Hospital said: "A lot of things we think are due to testosterone deficiency are actually related to the oestrogen deficiency that accompanies it."
The study involved 400 healthy male volunteers aged 20 to 50 and it was shown that some of the testosterone men produce is turned into oestrogen, with both levels reducing as they get older.