Speculative claims that circumcision has an adverse effect on breastfeeding outcomes (starting breatfeeding, breastfed at 1 month of age, exclusively breastfed at 4 months, stopping breastfeeding due to poor response, duration of breastfeeding), child health (gastrointestinal, lower respiratory illness, eczema, asthma for ages 0-2 y), cognitive ability outcomes later in childhood (IQ at ages 8-9 y, scholastic ability scores at age 13) have been dismissed by research findings of a well-designed (longitudinal) birth cohort study of 1000 males in New Zealand [174].

In fact respiratory tract infections in uncircumcised infants in this study were twice as high as in the circumcised (21% vs. 11%).