For instance, it may alter the level of sex hormones around the time of conception.
As every awkward adolescent or expectant mother knows, sex hormones can have profound effects on the body.
Our study confirms that high levels of sex hormones can raise risk.
But in the premenopausal years, a woman's sex hormones start to change.
For example, one way to track the reproductive cycle in a female is to follow the waxing and waning of sex hormones.
The extinction of elephants, the threat of mad-cow disease, outbreaks of the Ebola virus, and chemicals that mimic sex hormones are all fashionable.
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.
The study also found that women with raised levels of a molecule called sex hormone binding globulin, which reduces the activity of sex hormones, were at lower than usual risk.
Although the old ovary had shut down during chemotherapy, the new additions sprang to life, producing sex hormones which allowed her eggs to develop and her menstrual periods to resume.
The EU scientific committee for vetinerary measures has warned that all sex hormones used in the US could pose a risk of cancer, genetic problems and brain disease, and claims children are most at risk.
While oral contraceptives have a good safety record (and Barr Laboratories' trial of 1, 400 women showed no evidence that Seasonale is riskier than conventional contraceptive pills, except for a higher incidence of irregular bleeding in the first few months of use), Dr Hitchcock is keen to see women exercise caution when it comes to prolonged use of anything containing sex hormones.
The researchers ruled out radiation as a possible cause of the apparent sex reversal but suggested environmental contaminants that mimic hormones or water temperature changes could be the culprits.
Gary Thorgaard, director of Washington State University's School of Biological Sciences and a co-author of the paper, says the experiments in his laboratory and others have shown it is possible to reverse the sex of trout embryos through the use of hormones.
For a child born of indeterminate sex they will undergo number of tests including those involving chromosomes, hormones and internal organs.
These hormones include cortisol (which is related to stress), estradiol (the main female sex hormone) and prolactin (which, as its name suggests, triggers her breast tissue to develop the ability to secrete milk).
应用推荐