parshanut torah comment - What happened to the bechorim (first-borns)?

In the begining of sefer bamidbar, the males between 20 and 60 are counted and it says that there are over 600,000 of them. Theoretically each, or most, of these people should have had a first-born child and half of these children should be males. But two prakim later, the first-born males one month old and up are counted and instead of there being about 300,000, there are only about 22,000. Why are there so few?

I checked several mefarshim and none of them seemed to have an answer.

Answer

Some portion of the 600k males were not married, and some of the married ones had no children at all.

Of those that were, only 22k families had first-borns which needed to be redeemed by a Levite or 5 shekalim. Not all firstborns need redemption, in fact, a Pidyon heBen ceremony is relatively rare.

1. As you already noted, the child must be male.


2. If the child was preceded by a non-viable child, it is exempt.



3. The child must have born naturally (i.e. males born via C-section are exempt).


4. Neither the father nor the mother may be a member of the tribe of Levi.


5. Some percentage of the remainder were no longer alive.


6. The son must have been born first for certain - if there were twins and it isn't certain which arrived first, there is no redemption. (Recall that Jewish mothers gave birth on their own, to 6 at a time, in the fields, sometimes abandoning their children. It is likely that many were unsure which was the first born).