Demographics

As of November 1, 2022, the Registry has 9,871 twin pairs (19,742 individuals). New pairs are enrolled on a quarterly basis. Below is a detailed breakdown of the Twin Registry population, calculated from the survey that twins complete when they join the Registry.

Age

Age group% at enrollment% today
9 and younger5.84.1
10-1919.92.7
20-2919.26.2
30-3914.327.6
40-4911.817.8
50-5912.313.5
60-6911.213.6
70+5.714.6

Ethnicity
Hispanic/Latino: 4.0%

Race
One race: 96.9%
White: 90.0%
Black or African American: 2.0%
American Indian or Alaska Native: 0.6%
Asian: 2.5%
Native Hawaiian or Other Pacific Islander: 0.4%
Some other race: 1.4%
Two or more races: 3.1%
White and Black or African American: 0.5%
White and American Indian or Alaska Native: 0.8%
White and Asian: 0.9%
Two or more other races: 1.0%

Zygosity
Identical: 53.2%
Fraternal: 46.8%

Sex
Male/Male pairs: 28.6%
Female/Female pairs: 49.9%
Male/Female pairs: 21.6%

Zygosity/Sex
MZ Male pairs: 19.2%
MZ Female pairs: 34.0%
DZ Male pairs: 9.4%
DZ Female pairs: 15.8%
DZ Male/Female pairs: 21.6%