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Table 1 Whole twin sample and sex specific characteristics

From: Sex differences in brain structure: a twin study on restricted and repetitive behaviors in twin pairs with and without autism

DemographicsAll (N = 150)Males (N = 88)Females (N = 62)χ2, P
Number of pairs754431 
Age mean (SD)16.10 (3.31)15.90 (3.17)16.39 (3.51).61, .435
Age range9–23.6910.69–23.349–23.69 
N subjects zygosity MZ/DZ92/5850/3842/201.65, .198
N subjects ASD diagnosis322012.09, .769
N subjects ASD diagnosis per MZ / DZ15/177/138/4 
N pairs concordant for ASD633 
N pairs discordant for ASD20146 
N pairs ASD concordant per MZ/DZ4/21/23/0 
N pairs ASD discordant per MZ/DZ7/135/92/4 
N subjects ADHD diagnoses3423111.02, 0.312
N subjects Other neurodevelopmental disorders251690.14, 0.711
N subjects psychiatric diagnoses241410< 0.001, 1
N subjects No diagnosis7040300.04, 0.851
Age ASD discordant pairs, range16.21 (3.55)
10.69–23.34
17.70 (3.16)
12.86–21.52
15.58 (3.57)
10.69–23.34
3.14, 0.076*
Age ASD concordant pairs, range16.28 (4.08)
11.09–23.69
19.30 (3.47)
16.34–23.69
13.26(1.65)
11.09–14.43
8.43, 0.004**
Age non-ASD pairs, range16.03(3.14)
9.00–22.77
15.63(3.37)
9.00–22.17
16.36(2.94)
10.95–22.77
1.61, 0.205
  1. MZ monozygotic, DZ dizygotic. Concordant: both twins with ASD diagnosis, Discordant: only one sibling with ASD diagnosis. P values and chi-squares from test comparing males and females (χ2 tests for categorical, Kruskal-Wallis for numerical variables). Total number of participants for each diagnosis are displayed, but participants could have more than one diagnosis. N subjects gives the number of individuals, N pairs give the number of pairs (which includes two individuals)
  2. **= p <0.01, * p<0.05, . = p< 0.1