What are the odds of having 2 grandchildren born same day by 2 different children in same year?

The odds of having two grandchildren born on the same day by two different children in the same year can be estimated using basic probability. Assuming a year has 365 days and that births are evenly distributed throughout the year, the probability of one grandchild being born on a specific day is 1 in 365. If the first grandchild is born on a particular day, the chance that the second grandchild is also born on that same day is 1 in 365, leading to a combined probability of 1 in 365 for both. Therefore, while the odds are relatively low, they are not impossible.