Masculinity is controlled by the male hormones, which are called androgens. The most important of the androgens is a hormone called testosterone and nearly all the body's supplies of testosterone are made by the testicles.

Usually removing just one testicle will have little or no effect on the production of testosterone, with the remaining testicle being able to keep up a normal level of the hormone. Sometimes, however, men who develop testicular cancers may have testicles which are not working properly and only producing fairly small amounts of male hormone. In this situation removal of one testicle may mean that the one that is left behind cannot produce enough testosterone and the levels may fall sufficiently to cause some problems. Also, very occasionally, there may be cancers in both testicles and both will have to be removed which will lead to a fall in testosterone to an abnormally low level.

If changes in masculinity do develop in the months after an operation for testicular cancer and tests show that there is not enough testosterone in the blood then it is possible to have hormone replacement therapy (HRT) to increase testosterone levels.

There are a number of different types of HRT that can be tried. These include injections, tablets and patches or gels that can be applied to the skin.

Having HRT to increase the level of testosterone in the blood can help with some of the physical side of masculinity: it can continue the growth of male facial and body hair, it can keep a 'male' balance between fat and muscle in the body (men who have very low testosterone levels tend to develop more fat and lose some of their muscle tissue).

HRT can also help with some of the emotional or psychological side of loss of masculinity in about 3 out of 4 men. So men who find they are having problems with loss of interest in sex (reduced libido) or difficulty with getting erections or feeling low in mood and tired may find that HRT brings about a change for the better.