In early New England, only the children of church members could be baptized, and church membership was restricted to those who could convince the powers that they had experienced a conversion experience. Hence, many children were not baptized as infants. In some cases, a parent (either or both) joined the church after they had had several children, and it's relatively common to see a list of the children from a family baptized on the same day, sometimes on the same day as the parent. It's one reason a careful genealogist only uses baptism dates in the period as estimates for birth dares with some caution.