One thing about genealogy you certinly learn about the gestation time. I noted my family had premature eldest children at least four generations in a row.
Thank goodness we don't worry so much about it these days.
Consider good old Rabbie Burns he had three women pregnant at the same time and had promised them all he would marry them (didn't work).
His wife eventually took in one of his children by another woman and his brother's family yet another.
His wife made the celebrated remark to the effect "Poor Rabbie - he should have had twa wives" she seemed perfectly relaxed about it (at least she had him most of the time).
I have noticed that most modern wives don't have her sense of humour.
The fact that the Presbyterian Church were moral zealots and each church had its stool of penitance did not seem to stop boys and girls doing what came naturally. In a hard country with high infant mortality it was probably very necesary for plenty of children to be born. When a young couple were obviously unable to meet the burden of raising a child they did not necessarily marry. A system of fosterage/adoption amongst other family members existed. I have given you the example of Burns and this also existed
into fairly recent times - my Mother herself was fostered/adopted by her real Mother's Sister and her Husband who were themselves childless. It was practical, it worked, and the child stayed in the family.
So who you think you are is not always who you are and we all know the saying "its a wise child that knows its own father". DNA testing is not going to be for the sqeamish.