May 20, 2025
Some time ago, I wrote about mistakes genealogists make when they’re building online family trees. Lately, I’ve been checking out some online trees, and my inner schoolteacher is still astounded at the types of errors that people make. I thought I’d rerun part of that earlier column.
The trees make me wonder where the creators were when their high school class discussed basic biology. Clearly, they weren’t paying much attention. Here are a few rules of basic biology that might help some genealogists make entries in their family tree.
As far as I know, these rules haven’t changed in at least the last 400 years. This means although answers to genealogy questions are often based on the rule of “it depends,” there are a few constants. First, a mother and her child are always in the same place when the child is born. That is a fact. The mother and child may never be in the same place again, but for that one day, they are in the same place. If you have a proposed mother who never left Connecticut and a child who was born and lived in Georgia, you probably need to rethink. That New England woman is not likely the mother of that southern baby.
Another rule of basic biology is that the parents of a child had to be together at least once, about nine months before the child was born. If a man and a woman were on different continents at the relevant time, you may want to dig a little deeper.
Furthermore, people weren’t always married when they conceived a child, despite what Cousin Helen might have told you about your great grandparents. Although premature babies are always possible, the huge numbers of first baby preemies found on our family trees should be cause for suspicion, although not judgement.
Another basic biological fact is that women don’t give birth every six months as some family trees show. One of my second great grandmothers had eleven children, and how those children fit into the family has long been a subject of discussion among their descendants. Many of their trees show one of the children being born six months after my great grandfather, which is clearly impossible. As the old saying goes “A baby takes nine months, except for the first one” (see the above paragraph about that).
The bottom line is if something seems “off,” it probably is. The way to prevent these embarrassing mistakes is to think before you add data to your tree. These were actual people, and they followed the rules of nature, just like we do. We all make mistakes. Sometimes stupid ones crawl into our work, even when we try to prevent them. Spending a little time looking at how families fit together can help weed out some of the most egregious errors.
Carol Stetser
Researcher
Larimer County Genealogical Society