Sex differences in birth defects: A study of opposite-sex twins

✍ Scribed by Wei Cui; Chang-Xing Ma; Yiwei Tang; Vivian Chang; P.V. Rao; Mario Ariet; Michael B. Resnick; Jeffrey Roth

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 76 KB
• Volume: 73
• Category: Article
• ISSN: 1542-0752
• DOI: 10.1002/bdra.20196

✦ Synopsis

BACKGROUND: Sex differences in structural birth defects are often confounded by environmental risk factors. Opposite-sex twins provide a unique model for detecting sex differences in birth defects while maximally controlling environmental risk factors in a natural setting. METHODS: Population data from the Florida Birth Defects Registry were analyzed. A total of 4768 pairs of twins who were discordant for sex and born between 1996 and 2001 were analyzed. The McNemar test was used to compare the differences between a male twin and his twin sister for the risk of developing specific defects and organ-system defects. RESULTS: Of 4768 twin pairs, 225 males (4.72%) and 175 females (3.67%) had birth defects. Among opposite-sex twin pairs, males had a 29% higher risk for birth defects than their twin sisters. Compared to their twin sisters, males had a 5.4 times higher risk for pyloric stenosis and a 2.4 times higher risk for obstructive genitourinary defect, but only one-tenth the risk for congenital hip dislocation. CONCLUSIONS: Sex differences in birth defects exist between opposite-sex twins.