All of Judaism is dictated my Jewish Law, called Halacha.

Everything from dietry laws, the sabbath etc.,(even if it all seems obvious, it is still there to prevent any confusion and to spell out what you do in slightly different circumstances (twins etc, mother sick etc), it is all written down in either the five books of the Torah (Genesis - Deuteronomy), and the oral Torah, which used the be trasnmitted orally throughout the generation (this is normally the explanation on the 613 laws found in the Torah, rather than just the sentance), but was written down in a later stage to become to Talmud and Gemorrah (which i quoted above).

I do have to point out that i don't know how this applies today - i have never asked my Rabbi if we still hold that the law remains as such nowadays. I just thought it was interesting that traditionally this is what was practised.

But like you says Lix, it went without saying - first mother, and then wet nurse (which i think is the order today from the WHO & ABA?)

Pholmes - i don't know about what is written in the Christian bible, i don't study it, but maybe google it and see. The only difference is that Judaism (and i think Islam, correct me if i''m wrong), actually have a let of religious laws which spell out what to do, whereas Christianity doesn't, so it might not be written down as such. I don't think you actually find this law as one of the 613 in the 5 books of the bible, it will probably have been extrapolated from one and then expanded upon in the oral laws, so if you actually went reading through the bible, i wouldn't expect to see it there (i could be wrong, would need to go and read up myself!)