DOHaD research on preconception, prenatal, and early-life periods of human development can provide a critical resource for legal thinkers interrogating the lines of responsibility for environmental harms (both physical and psychosocial) that affect a child’s growth and development. DOHaD scholars who engage with epigenetic research offer an evidentiary narrative that traces the causal origin of early-life health harms to events that have occurred during pregnancy and prior to conception. Scientific research is increasingly providing evidence that those who suffer disadvantage throughout their lifecourse (in conditions of systemic oppression such as from racism, sexism, or poverty) may be disproportionately subject to molecular changes, creating harmed subgroups that are then intergenerationally reproduced as socially disadvantaged communities. Drawing examples from Australia, the United States, and Canada, this chapter asks what legal obligations, if any, should or can be imposed on contemporary society to ensure not just the future ’health’ of existing children (as they grow into adults) but also the generations of people yet to be born. It is argued that traditional common law legal responses that place responsibility on the individual rather than the community do not ensure intergenerational justice.