Did you see this? http://www.usatoday.com/story/news/nation/2015/01/02/new-years-baby-shares-birthday-with-parents/211...
Not to be a real nerd about this, but the odds of three people picked at random having the same birthday are only 1 in 48 million (assuming the distribution of birthdays is even, which it probably isn't). There are currently 115 million households in the US, so there are probably at least 2 families like that (sharing a birthday, but not necessarily New Years Day...)
the chance of them all having the same birthday and it being Jan 1st is 1/365th of 1/48 million.... so like a 1 in 17 billion chance... (and there are probably only like 1.5-2 billion households in the world).
BUT of course, people CHOOSE to who to marry (hopefully), and sharing a birthday, especially Jan 1 probably made them more likely to want to marry each other... so you can't assume thats a random chance. :-P
The likelihood of randomly having the same birthday as your parent (by chance, without any kind of planning) is a much more frequent 1 in 133k... Meaning about 2480 people in the US alive now born on the same day as one of their parents... meaning probably about 6 or 7 born on January 1st. How many of those 7 parents were weird enough to pick a partner w/ the same birthday?
OK, I have way too much time on my hands... :-P
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