answer:You can read this about it if you have the time:
http://bespin.stwing.upenn.edu/~upsych/Perspectives/1999/sambur.htm “Currently, there are societal pressures to decrease the use of gender-biased language. However, some aspects of language might encode gender differences less obviously. When two words are conjoined, the ordering of the words does not change the grammar of the phrase. For most cases, either of the two words could occur first in the conjunct because English grammar is neutral concerning the ordering of phrases. “Jack and Jill” and “Jill and Jack” mean exactly the same thing. Yet, certain words are “frozen” in a specific order. Cooper and Ross (1975) found that these freezes occurred with a certain consistency. Some of the semantic constraints include male before female (husband and wife; and Peter, Paul and Mary), adult before child (cat and kittens), positive before negative (good and bad), and animate before inanimate (horse and buggy). This male first bias, although it is only a bias and not a rule, seems to extend beyond frozen phrases to more fluid structures. Thus the above frozen example of husband and wife is representative of conjunctive phrases that generally possess the male first bias.”