Look at your fingers. Which is longer? Is it the index finger (the finger you use to point with— technically the second digit, or 2D, counting the thumb), or the ring finger (the fourth digit, or 4D)?

The relative length of the index and ring fingers is known as the digit ratio or the 2D:4D. For example, if your index finger is 2.9 inches (or 7.4 cm) long, and your ring finger is 3.1 inches (or 7.9 cm) long, your digit ratio is 0.935 (i.e., 2.9/3.1 or 7.4/7.9). Men typically have lower digit ratios (the ring finger in males is typically longer than the index finger) than females (the fingers are about the same length in females). The ratio does not change much with age.

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