While reproduction is generally agreed to be a crucial feature of life on Earth, many of its roles in evolution are disregarded in discussions of biological individuality, by reducing reproduction to replication and copy making. The great diversity of reproductive modes explored by organisms during evolution are thereby treated as alternative strategies with a single purpose: to maximize fitness. This leaves many aspects of reproduction unconsidered, such as the effects of the diverse reproductive modes on the characterization of the entities relevant for biology. Recent reflections on the nature of the reproducing relation call for reconsidering the material processes involved in reproduction (Griesemer 2014, 2016, 2018), and evo-devo seems to be the natural disciplinary candidate for integration of reproduction and development into the structure of evolutionary theory. However, the theoretical implications of an “evo-devo of reproduction” have remained largely unexplored so far, also due to its focus on the evolution of body parts and their interactions.
In this contribution, we will reflect on the biological status of the pregnant female within this framework. We will argue that recent research in eutherian pregnancy and its evolution may have philosophical implications for our understanding of reproduction and individuality. The question whether the pregnant female is a carrier of independent developing individuals, or a single individual by itself, is becoming a focus of debate in the philosophical literature (Kingma 2018). The “fetal container model” has prevailed in the scarce philosophical thoughts dedicated to the question (Smith & Brogaard 2003), and is also the implicit choice in the biological and medical literature. In contrast, Kingma has recently argued in favor of understanding the pregnant female according to a part-whole model and her claim states that the fetus is part of the gestating organism. Our aim here is reissue/retake this discussion from a biological standpoint rather than the metaphysical one favoured by Kingma´s work.