“Women are wonderful” effect
The “women are wonderful” effect is the phenomenon found in psychological research which suggests that people associate more positive attributes with the general social category of women compared to men. This effect reflects an emotional bias toward women as a general case. The phrase was coined by Eagly & Mladinic (1994) after finding that both men and women participants tend to assign exceptionally positive traits to women (men are also viewed positively, though not quite as positively), with woman participants showing a far more pronounced bias. The authors supposed that the positive general evaluation of women might derive from the association between women and nurturing characteristics.
Eagly and Mladinic In a review conducted by Eagly, Mladinic & Otto (1991), significant evidence was found to indicate that women were evaluated positively as social category and significantly more favorably than men. In the experiment, over 300 college students (both men and women) evaluated the social categories of men and women, relating the traits and expectations of each gender through interviews, emotion-associations and free-response measures. Supporting this effect, words regarded as positive, such as “happy”, “good”, and “paradise”, were more readily ascribed to women more than men.
Rudman and Goodwin Rudman & Goodwin (2004) conducted some of the first research  on gender bias that measured gender preferences without directly asking the participants. Subjects at Purdue and Rutgers participated in computerized tasks that measured automatic attitudes based on how quickly a person categorizes pleasant and unpleasant attributes with each gender. For example, similar to Eagly, Mladinic & Otto (1991), the tasks could determine if people associated pleasant words (good, vacation, and paradise) with women, and unpleasant words (bad, slime and grief) with men. The results, which agreed with the “women are wonderful” effect, showed that while both women and men have more favorable views of women, women's in-group biases were four times stronger than men's.
Other experiments in this study found people showed automatic preference for their mothers over their fathers, or associated the male gender with violence or aggression. Rudman and Goodwin suggest that maternal bonding and male intimidation may influence gender attitudes. Another experiment found adults' attitudes were measured based on their reactions to categories associated with sexual relations; specifically, men with more sexual encounters tended to have a more pronounced positive bias towards women.
Despite the consistently-found effect, women are considered less valuable than men in at least some specific instances. One study has shown that women are judged more harshly in certain business roles, "especially when she worked in an industry incongruent with her gender role. Female and older participants showed more prejudice against the female leader than did male and younger participants." 
- citation needed
- esp unlikely given the date of field
- Alice H. Eagly and V. J. Steffen (1984), "Gender stereotypes stem from the distribution of women and men into social roles", Journal of Personality and Social Psychology 46 (4): 735–754, doi:10.1037/0022-35126.96.36.1995
- Eagly, Alice H.; Mladinic, Antonio; Otto, Stacey (1991), "Are women evaluated more favorably than men? An analysis of attitudes, beliefs and emotions", Psychology of Women Quarterly 15 (2): 203–16, doi:10.1111/j.1471-6402.1991.tb00792.x
- Eagly, Alice H.; Mladinic, Antonio (1994), "Are people prejudiced against women? Some answers from research on attitudes, gender stereotypes, and judgments of competence", European Review of Social Psychology 5: 1–35, doi:10.1080/14792779543000002
- Garcia-Retamero, Rocio; López-Zafra, Esther (2006), "Prejudice against Women in male-congenial environments: Perceptions of gender role congruity in leadership", Sex Roles 55 (1/2): 51–61, doi:10.1007/s11199-006-9068-1
- Rudman, Laurie A.; Goodwin, Stephanie A. (2004), "Gender differences in automatic in-group bias: Why do women like women more than they like men?", Journal of Personality and Social Psychology 87 (4): 494–509, doi:10.1037/0022-35188.8.131.524, PMID 15491274
- Whitley, Bernard E.; Kite, Mary E. (2010), The Psychology of Prejudice and Discrimination, Belmont, California, USA: Wadsworth, ISBN 978-0-495-81128-2