Background: Gender preference is prevalent in some communities and using medical techniques to choose the baby’s Sex may cause the gender discrimination and gender imbalance in communities. Therefore, evaluating the gender preferences and attitudes towards using Sex selection technologies seems to be necessary.Methods: This cross-sectional study was conducted in Avicenna Fertility Center. Participants were 100 women with one child who were referred for Sex selection. Data were collected through self-developed questionnaires. The questions were designed by the researchers at the experts’ panel. To determine the validity of the questionnaire, the viewpoints of professors specialized in these issues were obtained. The statistical analysis of the data was performed using SPSS software (Version 11.5), and p<0.05 was considered significant.Results: Tendency toward the male was more than female Sex (55.5% male, 15.5% female and 28.5% no tendency). Majority of participants agreed with Sex selection with medical reason and Sex selection in order to balance the family. Women's level of education had positive effect on agreements to fetal Sex selection with medical and non-medical reasons (p<0.001).Conclusion: Although gender preferences were toward the male Sex but this preference was not very strong. Most participants agreed with non-medical Sex selection for balancing the Sex composition of their children. It doesn’t seem that non-medical Sex selection for family balancing causes severe Sex imbalance in Iran.