Maternal 2nd to 4th digit ratio does not predict lifetime offspring sex ratio at birth.

The low ratio of second-to-fourth digit length (2D:4D) of parents, a putative indicator of high prenatal and even adult testosterone levels, has been suggested to predict a male-biased secondary offspring sex ratio. We investigated this question in 244 contemporary postreproductive Finnish women. Information on the lifetime offspring birth sex ratio of women was collected by questionnaires and the 2D:4D of both their hands were measured from scanned photographs. We found no evidence that the right hand 2D:4D, the left hand 2D:4D, the mean of the right and the left hand 2D:4D, or the difference between the right and the left hand 2D:4D was related to offspring sex ratio at birth among these women. Our results thus do not support the suggestion that offspring birth sex ratio is related to 2D:4D in women.