Risky Assumptions

My late mother-in-law, Mildred Hayes Koehler, was born and raised in Fleming County, Kentucky.  In fact, her ancestors settled in that area in the early 1800's, making my research of them fairly easy, other than the fact that they tended to use the same first names over and over.  But, that is another story!

Being a Kentuckian, Mildred enjoyed her subscription to the magazine, Kentucky Explorer.  As her daughter-in-law, I too enjoyed it as each issue was handed over to me to use in my hunt of the Hayes, Dailey, and Vice families.  As a result of my being a saver rather than the opposite, I have a rather large collection of back issues of this magazine that I am now passing on to my son who, like me, loves all things connected to history.

Looking through a February 1999 issue, I found the following in an article comprised of interesting tidbits from March 10, 1898 Kentucky newspapers.  

"Richmond, Kentucky - The wife of Henry White, of Paint Lick, this county, gave birth to a girl on Tuesday of last week and on Thursday, two days after, was delivered a bouncing boy."

Aside from being pretty interesting, I wondered what I would have thought if I had been researching this family and had not been privy to this explanation of why these twins had birth dates that were two days apart.  What if all I had found were genealogical records with only the dates of birth?

Would I have assumed there had been a mistake in the records?  Would I have assumed the two children were not siblings?  If I had found only one birth record, would I have automatically assumed the other twin had the same birth date?  Probably, probably, probably.  

Some assumptions are obviously risky; others not quite so.  Before I read about Henry White's little twins, I think I would have placed the assumption of twins having the same birth date as one of the "not so risky" ones.  Not so much now.  Have I made other assumptions that were "just plain wrong"?  What assumptions have you made in your research that might be riskier than you first thought?