How many kids does the average morman family have?

This varies greatly, and depends a lot on where the family lives. The Church of Jesus Christ of Latter-day Saints (commonly called the "Mormon" church) puts no set rule on how many children a family should have, it only follows The Bible's direction that says "Children are an heritage of the Lord". People may choose when to have children based on their desire, ability, medical condition, and financial status.

I have known Mormon families with no children, some with only one or two, and some with 13 to 15! An average Mormon family living the suburbs of Salt Lake City has between four and eight kids, while an average Mormon family living in Europe has one to three - it's just based on the culture where they live.