In our multicentre retrospective study assessing long-term health outcomes of 1000 children born to mothers with IBD, we found that anti-TNF-α and/or thiopurine use during pregnancy does not affect birth outcomes and the following long-term health outcomes of children: antibiotic-treated infections, severe infections needing hospital admission, adverse reactions to vaccinations, growth failure, autoimmune diseases and malignancies. The gene discussed is TNF; the disease is inflammatory bowel disease.