ovulate

When a woman ovulates, the typically impervious mucous barrier loosens up, allowing sperm to penetrate and fertilize eggs.

This means that if you have sex with a girl who then ovulates less than seven days later, she can't pregnant.

Head of pandas Iain Valentine said: "They will meet several times to have the opportunity to mate and then, as Tian Tian finally ovulates, artificial insemination will also take place."

During a normal menstrual cycle in which a woman ovulates (called an ovulatory cycle), a small number of follicles begin to grow.

So the week before your wife ovulates and three to four days after are the 'danger days'.

Shortly thereafter, the cow ovulates: the follicle ruptures and releases the egg into the uterus.

We prepare women with drugs, in the same way as IVF, to ensure that she ovulates at a fixed time and then introduce the sperm into the uterus instead of just into the neck of the cervix.

"But I never saw her ovulate." A successful mating revealed this rhino species is an induced ovulator (ovulates only after breeding, rather than on a periodic cycle).

When she ovulates the ovaries may release one or sometimes more ova, but all of those egg cells are produced on the one day; there is only one ovulation day in any cycle.

How long a woman ovulates may affect how well her body can build and maintain cancellous bone tissue (the spongy, flat, porous bone that makes up the pelvic area and rib cage), according to a research team from the University of British Columbia.