Since there can only be one first born per family then the number of families will be very close to the same number as the first born. Ignoring any exceptions which will make our calculation conservative we can find out how many fighting men were born to each family in Israel.

Fighting Men divided by families is equal to men per family.

603,550 ÷ 22,273 = 27.1

So you can now see that each family was responsible for just over 27 fighting men. This of course does not count any of the women. We could guess that each family had 27 women, however if the ratio of men to women was like it is now then that number is low. That means that each Israelite family would have had about 54 children. So if, as so many insist upon, each family only had one wife then she was having children well into her 60's and beyond if she had one each year.

A better answer to what was going on was that it was very normal in Israel for men to have more than one wife. This is during the time that Yahweh God gave the children of Israel His Law. There is not one mention of Yahweh God prohibiting polygyny. In fact He regulated it which gave it His approval.

By the way, if we go by today's numbers for children per wife in a polygynous family then each wife in Israel had around 4 children. We can then figure out an average number of wives per family.

Number of children per family divided by 4 equals the number of wives per family.

54 ÷ 4 = 13.5

As this is a continuing study I recently found this in

2 Chronicles 11:21.

"Now Rehoboam loved Maachah the granddaughter of Absalom more than all his wives and his concubines; for he took eighteen wives and sixty concubines, and begot twenty-eight sons and sixty daughters."

In this example we see that Rehoboam was consistent in the number of sons with twenty eight. We also see that he had a very large number of daughters above what we suggested.

Another example is Jacob/Israel. He had four wives (two wives and two concubines). The scripture records that he had twelve sons and one daughter. Three of his wives had two children each and the first had six sons and one daughter.

Each family in Israel may have had an average of thirteen or fourteen or so wives during the time of the count. I am sure that the number of wives varied with Israel's political status and their obedience to God. If they were free they had more wives. If they were under bondage they had fewer. True Israel is under bondage now and we have fewer wives per man. Isaiah 4:1 may yet come to pass however.

So we see that a man having more than one wife was the norm in Israel. Even if my non-Bible sourced numbers are off by fifty percent then the men of Israel still had many wives.