As of April 30, 2019, the Registry has 9,668 twin pairs (19,336 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 younger	3.8	4.2
10-19	21.3	1.8
20-29	19.3	12.9
30-39	14.4	27.7
40-49	12.0	15.2
50-59	12.4	13.3
60-69	11.2	13.6
70+	5.7	11.3

Ethnicity
Hispanic/Latino: 4.0%

Race
One race: 96.9%
White: 90.1%
Black or African American: 2.0%
American Indian or Alaska Native: 0.6%
Asian: 2.4%
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: 0.8%
Two or more other races: 1.0%

Zygosity
Identical: 52.9%
Fraternal: 47.1%

Sex
Male/Male pairs: 28.4%
Female/Female pairs: 49.9%
Male/Female pairs: 21.7%

Zygosity/Sex
MZ Male pairs: 19.0%
MZ Female pairs: 33.9%
DZ Male pairs: 9.4%
DZ Female pairs: 16.0%
DZ Male/Female pairs: 21.7%

Where are our members located?