Are animal models useful or confusing in understanding the human feto-maternal relationship? A debate

• There are significant similarities and differences in placentation among species.
• Animal model data have enabled more focused and efficient human investigations.
• Human studies are always obligatory as similarity does not equate with identicality.
• The implications for profitable future innovative work are set out.

The proposition “This house agrees that the proper study of man is woman” was debated. For those negating the proposition, the alternative was that “animal models are useful in understanding the human feto-maternal relationship.” Evidence for the proposition emphasized molecular and structural differences between the human and animal placenta and placentation. Evidence against the proposition and in favor of the alternative focused on functional and structural homologies, emphasizing that different molecules could be used in humans to achieve similar functional effects seen in animal (e.g., mouse) models. It was agreed that one always needed to test the validity of animal data by studying humans. The advantages and limitations of animal models were discussed.