10:13 Almost Every Day

Four individuals with identical birth month and day, in four generations, is indeed unusual, especially if there were few siblings. (The more individuals that are involved, the more likely two or more have the same birth month and day.)

With your conscious attention on the fact of four individuals in four generations having the same birth days, and wondering about the significance, it's expected that your attention would be directed to occurrences of those numbers when they exist in your environment. People tend to notice things related to current personal mysteries.

The number 10, among other things, is a leader and a starter. The number 13 is a number of methodically getting things done. When they exist together, however, they're likely to do things on a whim to express a sense of freedom.

It's likely each of the four individuals often (or persistently) expressed their personal sense of freedom at least during the first thirty years of their lives, if not longer — the period of their first pinnacle cycle.

As for the significance, it may be no more than a synchronistic set of circumstances. Or, it might contain much more personal significance for you personally.

Numerology is a great tool to determine tendencies and likelihoods as represented by associated numbers. But for determining significance of events, not so much. Perhaps one or more of the articles in the index to repetitively seeing certain numbers will provide information to help you find your answers.