# Pidyon HaBen rate

About how many pidyon haben ceremonies are required to be performed per 1000 Jewish births in the past few decades?

The requirements for a pidyon haben are:

• Both parents are Israel, not Kohen or Levi.
• Son is firstborn of the mother.
• No miscarraiges (after day 40 or 39) or stillbirths before the son.
• Vaginal birth.

One way to approximate this figure would be to multiply those statistics:

(PIsrael)2 * Pmale * (1−Pearlier miscarraige or stillbirth) * Pvaginal birth

Or, perhaps a better formula...

(PIsrael)2 * Pfirstborn is a male live birth * Pvaginal birth

Anyone have numbers on these?

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It's 1−P(earlier miscarriage or stillbirth) not 1/P(earlier miscarriage or stillbirth). But anyway I think a more natural thing would be to count proportion of live-born births among births to yield number of pidyonim (rather than count proportion of babies without an earlier stillborn birth or miscarriage). – msh210 Dec 3 '12 at 2:27
Note that some of these numbers can't be taken from general-population numbers. Proportion of vaginal births may be different (I'm guessing significantly higher) among religious Jews than among the general population. Proportion of firstborn males may be different among kohanim than among Jews (I have no reason to think so, but it's possible). The proportion of marriages between two non-Levites may be different from the square of the proportion of non-Levites. And so on. – msh210 Dec 3 '12 at 2:29
@msh210, I'm not a math person, but even if I were, I'm not sure I'd get your first comment. Prior stillborn births or miscarriages remove the need for a Pidyon on the next child. I don't know if I am misunderstanding your comment or if you are forgetting that. – Seth J Dec 3 '12 at 2:39
Another point to factor in is that not all previous miscarriages invalidate the next baby from having a pidyon haben. My wife had a miscarriage, but since it was early enough we were allowed to make a pidyon haben for the next baby with a brocha. – Michoel Dec 3 '12 at 3:41
@msh210 doesn't it make sense to count this not from the children, but from the women? That way you can disregard all of this "older sibling" stuff... Also, the formula is certainly meant for an approximation, not a real answer. A less approximated answer would be even better! – Charles Koppelman Dec 3 '12 at 15:45