- They don't proselytize at all, and there is even a dispute over whether one can choose to convert to Zoroastrianism, because some feel that it is an ethnic religion rather than a universal religion.
- There seems to be no real social pressure within the Zoroastrian community not to intermarry, and because conversion isn't encouraged, and children of intermarried parents are not necessarily considered Zoroastrian, intermarriage = fewer Zoroastrians. The New York Times article said that, "some Zoroastrian priests refuse to accept converts or to perform initiation ceremonies for adopted children or the children of intermarried couples, especially when the father is not Zoroastrian." Intermarriage is particularly an issue now that Zoroastrians live dispersed all over the world, and are not concentrated in parts of India and Persia (Iran) as they once were.
- Zoroastrianism believes in gender equality and full education for women, so many Zoroastrian women become very accomplished professionally, and have fewer children.
- The first is that while Judaism doesn't proselytize, it certainly accepts converts. The method of conversion may be in dispute, but there is no doubt that Judaism is both a nationality and a religion, and that you can become part of the "ethnic" (transmitted through birth parents) nation by accepting the religion in one form or another.
- The second is that there is social pressure not to intermarry in at least parts of the North American Jewish community, although if one doesn't adhere to the religion, it is hard to see the value behind marrying a Jew. I don't think that some sort of vague guilt is a strong enough inducement against intermarriage to last for more than a generation or two. There also seem to be a lot more Jews around than Zoroastrians, and they might be concentrated more in a few urban areas, so it is probably easier not to intermarry if you'd rather not and you're Jewish. (Not that there aren't Jews spread far and wide in the US and Canada, but if you wanted to marry a Jew, you could probably find a few marriageable ones in any decent-sized city in either country.)
Also, Conservative and Orthodox Judaism believes that the child of a Jewish mother and any father is Jewish, while Reform Judaism accepts any child of at least one Jewish parent as Jewish as long as they are raised in the Jewish faith (and not, say, also receiving formal instruction in Christianity). While intermarriage can often lead to assimilation in Judaism, it doesn't need to as it does according to some Zoroastrians.
- On the third issue, that of birthrate, I think we North American Jews probably have the same problems as the Zoroastrians, although we do have some Jews who have a boatload of kids. Still, average Jews in North America probably have fewer kids than average Christians or average Muslims in North America. (According to the April 2005 report, "Jewish Distinctiveness in America: A Statistical Portrait":
Despite having more stable marriages, Jews have smaller families than other groups do....They have fewer brothers and sisters than any other ethnic/racial or religious group (2.4 vs. an average of 3.8); they are tied with Italians for the lowest number of children ever born (1.6 compared to an average of 1.9), but do have more children than those with no religion (1.2) and Other Religions (1.4). They have the smallest current household size of any ethnic/racial or religious group (2.5 vs. an average of 2.9).
I guess what all of this makes me think is that it's both good to discourage intermarriage as a dilution of the faith, and to encourage conversion and adoption of Judaism as one's religion for those who want it. Doing the opposite, as the Zoroastrians are, is not a recipe for success. And that makes me sad.