Breastfeeding Outcomes and Cognitive Ability
Speculative claims that circumcision has an adverse effect on breastfeeding outcomes have been disproven by research. A longitudinal study in New Zealand found no difference between circumcised and uncircumcised boys in the following: starting breastfeeding, breastfed at 1 month of age, exclusively breastfed at 4 months, stopping breastfeeding due to poor response, duration of breastfeeding) [Fergusson et al., 2007]. There was also no difference in the following conditions concerning child health: gastrointestinal problems, lower respiratory illness, eczema, asthma (for ages 02 years), and cognitive ability outcomes later in childhood (namely, IQ at ages 89 years and scholastic ability scores at age 13). This well-designed birth cohort study involved 1,000 males in New Zealand born in the early 70s. In fact respiratory tract infections in uncircumcised infants in this study were twice as high as in the circumcised (21% vs. 11%).
Similarly, a study in Turkey found no difference in feeding frequency, nor in urination, stooling and serum bilirubin between 30 boys circumcised 2 days after birth compared with 30 not circumcised [Erog˘lu et al., 2008]. There were two who developed jaundice, but they were in the uncircumcised group.