However, the use of the male hormone to boost sex drive in women may not be risk-free.

CNN: Testosterone patch may kick-start sex drive in women

Without male hormone receptors to respond to testosterone, the researchers started to suspect androgen receptors were not the players they had been assumed to be.

ECONOMIST: Behaviour of the sexes

Vivus now is in middle-stage trials of a metered-dose spray of testosterone, the "male" hormone.

FORBES: Quest for Desire

These are the male sex hormone testosterone and desogestrel, a synthetic steroid found in the female pill.

BBC: '100% success' for male pill trial

Det Botha said police found two boxes of the male sex hormone testosterone and needles in Mr Pistorius's bedroom.

BBC: Pistorius witness 'heard shots, screams, more shots'

The men in these couples, she discovered, exhibited significant changes in their levels of cortisol, testosterone (the principal male sex hormone, and thus in some sense the masculine equivalent of estradiol) and prolactin over the courses of their partners' pregnancies.

ECONOMIST: Hormones and fatherhood

They said hormone treatments such as tibolone (Livial) which used male sex hormones called androgens, rather than female hormones, were more successful in increasing libido.

BBC: Sex a turn-off for many UK women

Jack also developed physical side effects including gynaecomastia (male breast enlargement), caused by the increased levels of the female hormone oestrogen in the body.

BBC: Newsbeat - Health - Young people 'double' steroid use

He claimed that a male partner in the delivery room can make a woman more anxious, slowing the production of oxytocin, a hormone which helps the labour process.

BBC: How it became almost mandatory for dads to attend the birth