For each chromosome contributed by the sperm there is a corresponding chromosome contributed by the egg, there are two chromosomes of each kind, which together constitute a pair.

The egg of every species of animal or plant carries a definite number of bodies called chromosomes. The sperm carries the same number. Consequently, when the sperm unites with the egg, the fertilized egg will contain the double number of chromosomes.

Man comes not from an egg but from an animalcule that is found in male sperm.

When we use fresh sperm, the surgical procedures for the sperm retrieval and egg retrieval need to be done the same day, and this may not be convenient for the couple. However, if we use frozen sperm, the man can have his procedure first, and if we find sperm, we can bank it. Then, at the couple's convenience we do egg retrieval and the fertilization procedure that puts the egg and sperm together. The model helps us know in advance when frozen sperm would allow for good results for that couple.

It's only a mature sperm that can fertilize an egg and eventually produce a baby.

When sperm and egg unite, something goes from inanimate to animate. It is life.