91 - 2D:4D digit ratio

Specifically, it is the ratio of the length of the index finger (digit 2, or "2D") and the ring finger (digit 4, or "4D") that is sexually dimorphic. Generally, males have a ring finger that is longer than their index finger. Females typically have index and ring fingers of about the same length. The ratio of index finger length to ring finger length is called the “2D:4D digit ratio,” or more simply, the “digit ratio.” Manning reports that, for males, the index finger is generally about 96 percent of the length of the ring finger, which gives an average digit ratio for males of .96. The digit ratio would be 1.00 if the ring and index fingers were the same length, and greater than 1.00 if the index finger was longer than the ring finger. Males generally have a digit ratio below 1.00 -- they have what is termed a "low digit ratio." Women generally have a digit ratio of about 1.00 (the index and ring fingers are of about equal length), or a "high digit ratio."


Some Characteristics That May Be Associated with Digit Ratio (from Manning, 2002)

Low 2D:4D ratio
Presumably due to relatively greater fetal exposure to testosterone in the 1st trimester

Males
More fertile
Higher lifetime reproductive success
More aggressive and assertive
Greater proclivity toward homosexuality/bisexuality
Higher musical and sports aptitude
Lower SES (?)

Females
Greater proclivity toward homosexuality/bisexuality
More aggressive and assertive


High 2D:4D ratio
Presumably due to relatively greater fetal exposure to estrogen in the 1st trimester.

Males
Higher risk of early heart disease

Females
More fertile
Higher lifetime reproductive success
Higher risk of breast cancer


For the whole article go to -
Link - 2D:4D