Finger Length Ratio (2D:4D) in Central India and an Attempt to Verify Fraternal Birth Order Effect: A Population Based Cross-Sectional Study

Abstract

Introduction: A normal physiology of a human being is not mere a series of functions occurring with specific intensities and timing. There are lot of factors that may change the normal physiological activity within normal limits. Finger length ratio is one of the markers of intrauterine androgen exposure and it is debated and contradicted by many authors. Digit ratio varies among the ethnicities. Many Indian studies show that there is considerable difference in finger length ratio in different population. Data regarding Central India was not found on extensive search. Aim: To find out the finger length ratio and explore the birth order effect on finger length ratio among the first two successive born in the said population. Materials and Methods: We conducted a survey on 1500 volunteer persons (800 male and 700 female) over two years of time. We measured the length of the index finger (2D) and ring finger (4D) of both the hands and asked about their birth order history to find out the digit ratio for Central India population and any existing correlation of the same with birth order. T Test and Analysis of Variance (ANOVA) were used for the measure of significance and difference among the groups. The p0.05) variation for finger length ratio of right and left hands observed in both male and female population. Conclusion: Our study reports that the finger length ratio (2D:4D) for Central India population did not show significant association between finger length ratio and fraternal birth order among the first two successive born.

Keywords

• digit ratio
• h-y antigen
• prenatal androgen exposure
• sex dimorphism