Question for the mathologically talented

[Connonym]

I don't know how to figure odds and stuff like but I'd like to know the odds of this -- my sister's best friend just had her 4th baby. All 4 were born spontaneously -- no induction, no C section, and all 4 were born on a Wednesday. It seems to me that the odds of having 4 children all born on the same day of the week would be pretty slim. Or am I full of shit?

[Orsino]

1. 1 in 343.

There's a 1 in 7 chance that the second child would be born on the same day as the first, again a 1/7 chance that the third would come on the same day, and 1 in seven for the fourth, too.

So, it's 1 over seven to the third.

[Dr. Strange]

2. Probability of four kids born on the same day: 1/343 like Orsino said.

Odds for such an even happening: 1 to 342. (Odds against would be 342 to 1.)