In her New York Times review of American Couple, Carol Tavris suggested potential bias in the Blumstein and Schwartz survey results, as most of the respondents were typically white, affluent, liberal, and well-educated.[6] Also criticizing the study was lesbian feminist theorist Marilyn Frye. Frye questioned the methodology of the survey format, feeling that the survey question is too ambiguous when applied to the sexual behavior of lesbian couples. Frye indicated that the survey's comparison is not accurate because the focus has been on sexual activity in which a penis is inserted and if "sex relations" is interpreted too narrowly, this ambiguity could account for the finding of a statistically low frequency of sexual behavior among lesbian couples.[7][8] Frye stated, "...What 85 percent of long-term, married couples do more than once a month takes on average 8 minutes to do...