Welcome to Week 3 Of Your Pregnancy:
At week 3, ovulation has occurred and the egg moves slowly into your fallopian tube, a tube that connects your ovary and uterus. Here is where it awaits fertilization by a sperm. Fimbriae, finger like structures that are located between your ovary and fallopian tube catch the egg when ovulation occurs and helps keep it on course. Having intercourse before or during this time may result in successful fertilization.
When Does Fertilization Occur?
Fertilization most often occurs within about one day of ovulation typically in the longest widest portion of the fallopian tube. At least 500 million sperm are ejaculated at the time of intercourse each carrying the father’s genetic code. Sperm is the smallest cell in the body and the male testis produces about 1000 sperm every second. It is a slow journey about 1/10th of and inch per minute. The sperm have to swin through the vagina, cervix and womb and only a few hundred will survive and only one will unite with a waiting egg, the largest cell in the body, carrying the mother’s genetic code. She made these eggs when she was a fetus herself inside her mother’s womb and have been kept in storage ever since. Only the strongest sperm reaches and penetrates the outer layer of the egg. Once this happens the membrane changes on the outer layer of the egg to prevent another sperm from penetrating. The winning sperm enters the egg and the sperm’s nucleus is attracted toward the egg’s nucleus and when united creates a human that never existed before and never will again and starts off a series of events that in 38 weeks will be your son or daughter.
When the sperm and the egg unite there is a combing of 23 chromosomes from the father and 23 chromosomes from the mother. Within these chromosomes are strands of DNA which will carry your baby’s genetic code. It takes 20 to 25,000 genes to make a human.
Genes are the instructions that tell us to become human instead of something else. This genetic material will determine your baby’s sex, eye colour, hair colour, body size and facial features. The sex of your baby is determined at the moment of conception. Of the 46 chromosomes that that make up your baby’s genetic material, two chromosomes are sex chromosomes one from the mother’s egg (always X) and one from your father’s sperm that could be an X or Y. If at fertilization the sperm with the X chromosome penetrates the egg the baby will be a girl (XX). If the sperm with the Y chromosome penetrates and unites with the egg the baby is a boy (XY). It is always the father’s contribution that determines whether the baby will be a girl or a boy.