Many diverse subjects are mentioned in the Qur'an in the course of inviting people to believe. Sometimes the heavens, sometimes animals, and sometimes plants are shown as evidence to man by God. In many of the verses, people are called upon to turn their attention to their own creation. They are often reminded how man came into the world, which stages he has passed through, and what his essence is:
(It is We Who have created you. Why, then, do you not accept the truth? Have you ever considered that (seed) which you emit? Is it you who create it? Or are We the Creator?) (The Qur'an, 56:57-59)
The creation of man, and the miraculous aspect of this, is stressed in many other verses. Some items of information within these verses are so detailed that it is impossible for anyone living in the 7th century to have known them. Some of these are as follows:
1. Man is not created from the entire semen, but only a very small portion of it (sperm).
2. It is the male that determines the sex of the baby.
3. The human embryo adheres to the mother's uterus like a leech.
4. The embryo develops in three dark regions in the uterus.
People living when the Qur'an was revealed, to be sure, knew that the basic substance of birth was related to the semen of the male emitted during sexual intercourse. And the fact that the baby was born after a nine-month period was obviously an observable event not calling for any further investigation. However, the items of information just quoted were far above the level of learning of the people living at that time. These were verified by 20th century science.