For most people making a baby is easier than falling off a log. Most women get pregnant without even trying to do so. Nature makes sex pleasurable, particularly around the time a woman produces an egg, so as to encourage us to procreate and have babies. The vital ingredients for making a baby are the sperm from the man, the egg from the woman and sexual intercourse around the time the egg is produced, so the sperm and egg can meet.
The ovary and the egg
When a girl is born, her ovaries contain many thousands of eggs, which are not mature. When you are only a 30-week-old foetus, your eggs stop developing and start to die. By the time you are born you only have one million left, and by the time you reach puberty this number has fallen to approximately 400,000. At puberty, the ovaries are activated and hormones are produced. Each month, a number of eggs are stimulated and one is chosen to mature. Ovulation is when this egg is released from the ovary.
This is usually around 14 days after the start of the last period, but can vary depending on the length of the menstrual cycle.
The sperm and the testes
When a boy is born, his testicles have the ability to produce many billions of sperm. At puberty this process is activated and the testicles act as sperm factories. Sperm is stored in the epididymis. Sperm takes about three months to be created from start to finish. When the male is aroused, the man’s prostate gland blocks the exit of urine and allows sperm and all the secretions produced by the glands to be ejaculated from the penis at the time of orgasm.
When egg meets sperm
Sexual intercourse is the natural process that allows the egg and the sperm to get together. When the man ejaculates between 200 and 300 million sperm are left in the vagina. Some fall out, some are destroyed in the vagina, some act as minders for the sperm that pass into the womb and on to the fallopian tube. Here the sperm look out for a newly produced egg. Once one sperm makes it into the egg, it blocks out any other sperm entering. Conception has occurred. The embryo makes its way back up the tube and into the womb, where it implants and begins developing.
The uterus (womb)
The uterus is where a woman carries her pregnancy. The neck of the womb (the cervix) sits in the vagina, allowing the sperm access to the egg. It also dilates in labour to allow the baby out of the womb. The womb is made of fibre and muscle (the myometrium), with a lining (the endometrium) that can allow a pregnancy to develop. If a ripe lining (endometrium) does not receive a pregnancy, it must be shed (menstruation, period) so a new lining can be made for another try at getting pregnant. At the top of the uterus there are fallopian tubes, which allow the egg from the ovary to get to the sperm. See Your Body »
Also known as the ‘neck of the womb’, your cervix is 3 to 4cm long. At one end it opens into the body of the womb (the uterus) and at the other end if opens into the vagina. The top half is muscular and stretchy, while the lower half contains a strong, tight band of fibrous tissue. The cervix produces secretions which vary according to the hormones produced in the menstraul cycle. See Your Body »
The womb has two fallopian tubes that allow eggs to pass from the ovary up to the womb, and that allow sperm coming from the vagina to meet the egg. See Your Body »
Further reading & information