I think that “women and children first” comes from basic biology.
One man can father any number of children with any number of women . . . yet a woman can carry only one pregnancy at a time.
This means that a species’ survival is more dependant upon a greater number of femaĺes rather than a greater number of males. This is something that was understood in the 1940s through the 1970s when Native American women were routinely sterilized without their knowledge and/or informed consent. As many as 25% of all Native American women (in that era) were sterilized, but the men were not treated in this way.
This idea that more women means more survival is–I believe–the source of “women and children first.”
As for the kids, survival of the children means that there’s more of the lifespan for the species to survive. Children are–after all–the hope for the future.