# 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?

• 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, 2012 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, 2012 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. Dec 3, 2012 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. Dec 3, 2012 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! Dec 3, 2012 at 15:45

In the United States in 2012, 1,570,976 of the 3,952,841 live births, or 39.7%, were the first live birth to that mother. Among mothers listed as non-Hispanic and white (which I mention only because I think the vast majority of Jews in the States are so listed and the category is available to me), 895,171 of the 2,134,044 live births, or 41.9%, were the first live birth to that mother. However, the proportion among mothers listed as white (irrespective of being listed as Hispanic) was 1,190,207 of 2,999,820, or 39.7%, and some of the considerations that lead to a higher percentage among non-Hispanic white mothers (i.e. a lower percentage — 310,326 of 907,677, or 23.2% — among Hispanic white mothers) may also lead to a lower percentage among religious Jewish mothers.

In the United States in 2012, 2,650,744 of the 3,952,841 live births, or 67.1%, and 1,441,894 of the 2,134,044 non-Hispanic white mothers' births, or 67.6%, were vaginal.

Source: the CDC.

So, assuming that half of all babies born are male, we can use 20% as a reasonable estimate for Pfirstborn is a male live birth and 67% as a reasonable estimate for Pvaginal birth.

According to Doron Behar, et al. in a 2003 paper in the American Journal of Human Genetics, citing a 1999 paper by Neil Braman et al. in Population Specific Polymorphisms, "it is estimated that Cohanim and Levites each comprise ∼4% of the Jewish people." Therefore, we can use 92% as a reasonable estimate for PIsrael.

Therefore, we can estimate that the proportion of live births that would require a pidyon haben would be:

(PIsrael)2 * Pfirstborn is a male live birth * Pvaginal birth ≈ 11%

• can we really use these stats for religious jews? Mar 25, 2018 at 19:40
• @heshy, eh. With a heavy grain of salt.
– msh210
Mar 25, 2018 at 21:20