出典:Wikipedia
出典:『Wikipedia』 (2011/06/18 09:53 UTC 版)
The digit ratio is the ratio of the lengths of different digits or fingers typically measured from the bottom crease where the finger joins the hand to the tip of the finger. It has been suggested by some scientists that the ratio of two digits in particular, the 2nd (index finger) and 4th (ring finger), is affected by exposure to androgens e.g. testosterone while in the uterus and that this 2D:4D ratio can be considered a crude measure for prenatal androgen exposure, with lower 2D:4D ratios pointing to higher androgen exposure. The 2D:4D ratio is calculated by measuring the index finger of the right hand, then the ring finger, and dividing the former by the latter. A longer index finger will result in a ratio higher than 1, while a longer ring finger will result in a ratio of less than 1.