In LLL's Facts about Breastfeeding 1995 the following reference is listed in relation to "The observed deterioration in male infants' ability to breastfeed after circumcision may potentially contribute to breastfeeding failure..." Howard, C. et al. Acetaminophen analgesia in neonatal circumcision: the effect on pain. Pediatrics 1994;93(4):641-46. Hope this helps. Natalie J. Shenk, BS IBCLC Ohio, USA