Introduction: The desire of the human to control the gender of fetus prior to conception has always been important. The aim of this study was to determine the role of maternal diet on fetal gender. Materials and Methods: In this narrative review study, a comprehensive review of databases including Pubmed, Scirus, Cochrane library, ScienceDirect, MD Consult, google scholar, Iranmedex, Magiran, and SID from 1982 to 2013 was performed. Key words to search databases included fetal sex, sex ratio, sodium, potassium, magnesium, calcium, fructose, eating disorders, sex selection, maternal diet, Ionic diet, fatty acid, calorie, and famine. Results: Results of studies on the effects of nutritional deficiencies and disorders on sex ratio were controversial. Studies showed that a combination of environmental factors such as stress, time of conception and maternal diet had effects on sex ratio. Preconceptional nutritional status of mothers was very important in changing sex ratio. Increasing the intake of K + + Na+ / Ca 2 + + Mg2+ in diet and high calorie diet could increase the ratio of male offsprings. Conclusions: Preconceptional diet was important in fetal sex ratio. However, low sample size in most human studies and the complex mechanisms of sex determination make it difficult to conclude definitively on this issue. Further human studies with larger sample size in this field are suggested.