It used to be said of a pregnant woman that she had "conceived," or that a "conception" had taken place inside her body. Today, these terms are rarely heard in everyday speech, and many people may now find them pretentious and melodramatic. Nevertheless, scientists still fall back on the word "conception" as a matter of course when they want to refer to "the beginning of a new life" or "the beginning of the existence of a new individual".
However, these seemingly simple definitions cover a very complex phenomenon that even now is far from being fully understood. Consequently,
not all scientists use the word "conception" in the same way.