Men can bear witness from the beginning of their sexual maturity at children, and it will change until her death is not really much. Of course the efficiency of sperm and thus the fertility with age somewhat, but generally, a man with every sexual intercourse to father a child. The fertility of the woman on the other hand is much less linear. Unlike the men it produces the germ cells do not always “fresh”. Women are born already complete with all the eggs to them in their lives or rather in the time of puberty until the menopause available. During this period, the fertility of the menstrual cycle subject: There are a few fertile, and much more infertile days.
Each girl has been at the birth of around half a million immature eggs, of which not all develop into mature oocytes, many of them do not even survive until puberty. After the onset of puberty matures every month in the menstrual cycle an egg in one of the two ovaries approached, is released (ovulation) and travels through the fallopian tubes to the uterus each. During this trip, the egg can be fertilized, so that from the egg and sperm can result in a child.
If it comes to fertilization of the ovum, the resulting embryo travels through the fallopian tubes into the uterus and implants in the uterine lining that has built up the body specifically for this purpose. If this succeeds, and the embryo implants itself well formed at the interface between embryo and uterus, the placenta, which are important for the child’s care during the pregnancy is. If it does not lead to fertilization, the body builds the endometrium has become unnecessary and rejects it again . then this is the menstrual period.
The time window for fertilization is compared to a monthly cycle quite small, there are basically only around 24 hours a day, which can occur relatively safe pregnancy. The concept of fertile days is almost too optimistic, the best chance of getting pregnant in the 12 to 24 hours immediately after ovulation. The fertile period can be very handy with an ovulation calculator, but also determine ovulation by that measure hormone levels in urine.