Egg cells are needed to create new life, as are sperm cells.
At the moment of birth the ovaries of a girl each contains 200.000 immature egg cells.
An egg cell is very small, smaller than the dot at the end of this sentence.
Starting at puberty, the ovaries release an egg cell once a month. The moment the egg cell ruptures and is released is called ovulation.
Fertilization can take place when a sperm cell is present at the fallopian tubes at the moment of ovulation. When fertilization doesn’t take place within 48 hours the egg cell dies off.
The egg cell contains genetic material, which - in conjunction with the genetic material of the sperm cell - determines what the child will look like.