Social science is commonly used in debates about controversial issues, especially for those concerning human sexuality. However, caution must be exercised in interpreting such social science literature, because of a variety of methodological and theoretical weaknesses that are not uncommon. Families are complex structurally and over time; such data are not easily analyzed. Merely determining the number of, for example, sexual minority families has been a difficult task. While some new theories are popular with social scientists, for example, sexual minority theory, they are often used to the exclusion of other, equally valid theories and often are not well tested empirically. Some types of families remain relatively unexamined. Social scientists can be biased by their own values, which are reflected in weak use of theory and in a variety of methodological problems. Eight studies are presented as examples of probable confirmation bias, in which methods and theory were modified in unusual ways that may have affected the outcomes and conclusions. Suggestions for improving social science include greater attention to effect sizes rather than statistical significance per se, deliberately minimizing the politicization of science, developing a culture of humility with respect to social science, deliberately reducing common biases, and maintaining a deeper curiosity about social science than is often seen. Scientists must be open to seeing their best “sacred cow” ideas or theories disproven or modified with increases in research on such issues. Summary In controversial areas of social science, there can be numerous threats to the validity of science. Here, some of the more common risks for social science research and theory are examined, with several specific illustrations of how bias appears to have crept into social science, often as confirmation bias. Recommendations are made for reducing bias in future research.