Table 5.

Novel parameterization of the fraternal birth order effect in men

						95% CI
	b	SE	Z	p	OR	Lower	Upper
Intercept	1.73	0.42	4.13	< .001	5.65	2.49	12.86
Sibship size	− 0.40	0.10	− 4.16	< .001	0.67	0.55	0.81
Maternal older siblings	0.46	0.12	3.86	< .001	1.59	1.26	2.01
Maternal older brothers	0.23	0.12	1.96	.050	1.26	1.00	1.60
Maternal younger brothers	0.20	0.12	1.62	.106	1.22	0.96	1.54
Age	− 0.00	0.00	− 0.80	.423	1.00	0.99	1.01
Mother’s age at target’s birth	− 0.06	0.01	− 4.67	< .001	0.94	0.91	0.96

Estimates represent the log odds using heterosexuals as a referential value