Does the sex of one’s co-twin affect height and BMI in adulthood? A study of dizygotic adult twins from 31 cohorts

Table 2 Adjusted means and regression coefficient for height (cm) and BMI (kg/m²) in females and males from same- and opposite-sex twin pairs

Phenotype	Twin type	Mean	95% confidence intervals	Regression coefficient	95% confidence intervals
Height	SS females	164.7	164.6, 164.8
	OS females	165.0	164.9, 165.1	0.31 cm	0.20, 0.41
	SS males	178.4	178.3, 178.4
	OS males	178.5	178.4, 178.6	0.14 cm	0.02, 0.27
BMI	SS females	23.95	23.90, 24.00
	OS females	24.00	23.05, 24.05	0.05 kg/m²	−0.02, 0.12
	SS males	25.20	25.16, 25.25
	OS males	25.26	25.22, 25.31	0.06 kg/m²	0.00, 0.12

The results are adjusted for cohort, age and birth year, and the non-independence (clustering) of observations within twin pairs
SS same sex, OS opposite sex, BMI body mass index