Gender bias -- a prejudice or even a preconceived bias for or against a party on the basis of gender -- is not "a harmless error" that appeals courts ignore.
Though less frequent than at one time, evidence of gender bias has led to reversals on appeal. For example, in a 1992 California case, an appeals court reversed a lower court divorce decision to uphold a prenuptial agreement. During the trial, the judge referred to the wife as "a girl" who was "lovely" but had "nothing going for her except her physical attractiveness." In ruling against the wife, the judge also rhetorically asked, "And why ... do you buy the cow when you get the milk free?" The appeals court came down on the judge, charging that his ruling had a whiff of "romantic paternalism" and lacked the appearance of justice.
Courts have also ruled that the gender of a party who is the homemaker should not affect the spouse’s noneconomic contributions when it comes to property distribution. Courts may not view a man as a slacker if in a marriage he assumes the role of homemaker and the wife works outside the home. In a 1992 Iowa case, the court said, "It is important, however, that we respect the rights of individuals to designate a primary wage earner during marriage and erase any gender bias that because [the husband] is male it was incumbent for him to have employment."