When you have dates of birth for children of a couple, make certain they are listed in that order on all charts and reports where children are listed. That makes it easier to see gaps in the birth of children. Those gaps could be due generally to the fact that there was a time period where no pregnancies took place, children who died young, children who have been overlooked (because they lived with other families, moved away at a young age, etc.) or the mother having miscarriages.
If you do not have dates of births or good estimates of the year of birth, determine if there are records that can allow you to determine anything about the order in which the children were born: year of first marriage, year of their own first child being born, etc. If you use records that suggest an order of birth indicate in your notes on the couple how you arrived at that order–don’t just order the children without documenting how you arrived at that ordering.