I am speaking purely from a scientific point of view (I am an atheist).
If an embryo only has 24 chromosomes instead of 46:
(1) the embryo is immediately aborted naturally. There are not enough info for the embryo to develop into a fetus.
(2) by some miracle, if the embryo is not aborted, it will become a grossly deformed fetus possibly with missing body parts. The fetus will then die.
(3) if, by some miracle, the fetus does survive and is born with very very very serious serious serious health problems and disfigured. The child will not be able to survive for long after birth.
(4) if by some miracle the child survives and reaches puperty, he/she will be infertile. There are not enough chromosomes for meiosis to occur. Without meiosis, gametes (sperms and egg cells) can't form. In other words, the individual is as "anatomically impaired as a candle."
(5) if by some miracle the individual's sex organs can have meiosis taking place (which at this point I can't see how this is possible at all), the individual can only mate with other miraculous individuals who have 24 chromosomes in order to produce 24 chromosomed offsprings.
(6) Then, the whole process of miracles happen all over again.