Homes built before 1978 may contain lead. The Lead Law protects a child's right to a lead-safe home. It requires the removal or control of lead paint in houses with children under 6. If houses built before 1978 are being sold or rented, sellers, real estate agents, and owners who rent their homes are required to notify their buyers and tenants of lead risks.
https://www.mass.gov/the-massachusetts-lead-law?
It is illegal to refuse to rent to families with minor children for any reason. Frequently landlords refuse to rent to families with children under the age of 6, due to the presence of lead paint in the unit. Landlords believe it will cost too much to remove the lead hazard in their units and therefore discriminate against families with young children. This refusal to rent violates the Massachusetts Lead Poisoning Prevention and Control law and federal and state fair housing laws.
https://www.massfairhousing.org/housing-discrimination/families-with-children-and-lead-paint
Your best hope is someone without small children show up with better income and credit score, so that your refusal to rent is based on income/credit and not based on having small children.
