As of June 30, 2019, the Registry has 9,722 twin pairs (19,444 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	4.7	3.8
10-19	20.3	1.7
20-29	19.2	11.7
30-39	14.4	26.8
40-49	11.9	14.6
50-59	12.4	13.0
60-69	11.2	13.7
70+	5.7	14.7

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: 53.0%
Fraternal: 47.0%

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: 9.3%
DZ Female pairs: 16.0%
DZ Male/Female pairs: 21.8%

Where are our members located?