ACTUALLY...Conception does not always create a human..
Conception CAN create a "Molar pregnancy"...Which is NOT a person.
A molar pregnancy refers to a pregnancy that is a type of gestational trophoblastic disease. It can refer to either a complete or a partial mole. Throughout the United States and Europe the incidence is about 1/1000 and 1/2000 pregnancies.
This occurs when the nucleus of an egg is either lost or inactivated. The sperm then duplicates itself because the egg was lacking genetic information. Usually there is no fetus, no placenta, no fluid and no amniotic membranes.
Partial Mole
This most frequently occurs when two sperm fertilize the same egg. There may be partial placentas, membranes or even a fetus present in a partial mole. However, there are usually genetic problems with the baby. Rarely, a partial mole will exist with twin pregnancy, however, the other twin rarely survives
SO OBVIOUSLY, A sperm and egg meeting does not always creat a FETUS, specifically in a MOLAR PREGNANCY.