Table 4. Standardised incidence ratios comparing childhood cancer incidence rates in the offspring of RTs to SEER and Connecticut registry rates (n=100 115)a.

	Offspring of females						Offspring of males
	Males			Females			Males			Females
	O	E	O/E (95% CI)	O	E	O/E (95% CI)	O	E	O/E (95% CI)	O	E	O/E (95% CI)
SEER registry comparison
Leukaemia	37	30	1.2 (0.9–1.7)	26	24	1.1 (0.7–1.6)	11	9	1.3 (0.6–2.2)	8	7	1.2 (0.5–2.4)
Lymphoma	33	20	1.7b (1.2–2.4)	14	14	1.0 (0.6–1.7)	10	6	1.7 (0.8–3.1)	3	4	0.8 (0.2–2.2)
All sites	120	114	1.1 (0.9–1.3)	101	99	1.0 (0.8–1.2)	39	33	1.2 (0.8–1.6)	24	29	0.9 (0.5–1.3)
Connecticut registry comparison
Leukaemia	37	32	1.2 (0.8–1.6)	26	24	1.1 (0.7–1.6)	11	9	1.2 (0.6–2.1)	8	7	1.2 (0.5–2.3)
Lymphoma	33	21	1.6b (1.1–2.2)	14	14	1.0 (0.5–1.7)	10	6	1.6 (0.8–2.9)	3	4	0.7 (0.2–2.1)
All sites	120	113	1.1 (0.9–1.3)	101	99	1.0 (0.8–1.2)	41	36	1.1 (0.8–1.5)	24	28	0.9 (0.6–1.3)

E=expected; O=observed; RT=radiologic technologist; SEER=Surveillance Epidemiology and End Results.

^aExcludes data on 5826 subjects with missing gender or whose parent reported a race other than white.

^bP<0.05.