In employing the term ‘maternal’ we are often referring to a ‘maternal instinct, ‘bond’ or ‘relationship’ – this last being my intended use. A quick Internet search reveals the maternal relationship to be a bond between a mother and her child. The relationship is typically thought to be continuous in its development, with its foundation beginning in pregnancy and childbirth. The maternal relationship is an important one. We need only look to examples of other non-human animals (mammals, amphibians, birds, fish, reptiles, invertebrates, etc) to understand its importance, if nothing else, for survival. Think of, for instance, the elephant mother. After 22 months of pregnancy she gives birth to a baby elephant: blind and dependent. The biological mother and the other female elephants in the group, called ‘allmothers’, care for the child until it can care for itself. For humans, the maternal relationship has been shown to lay the groundwork for social, emotional and cognitive development. As such, the maternal relationship has often been accorded a certain sacred status in society. As the use of assistive reproductive technologies (ARTs), and the practice of adoption, proliferate, they challenge our existing conception of the ‘maternal relationship’, forcing us to re-visit our assumptions and re-engage with our existing conceptions. ARTs are technologies that assist in achieving and monitoring a pregnancy – one of the most common being in vitro fertilisation (IVF). The use of egg donors means that intended mothers can now carry babies that are not their own genetic child; in addition surrogates can carry an intended mother’s genetic child (gestational surrogacy) or non-genetic child (traditional surrogacy). Surrogacy arrangements, in particular, challenge our conception of the maternal relationship as a bond with its foundations in pregnancy and childbirth. Partially an attempt to protect this birth mother-child bond, in the UK when a surrogate gives birth she has an absolute right to change her mind. In the past 20 years, however, there have only been two reported cases of surrogates seeking to keep the baby that was not theirs. Studies on the experience of surrogate mothers have largely found that surrogates do not possess an overwhelming maternal bond with the child they carry. In my own research speaking with egg donors and surrogates, many women describe themselves as partakers in the process of helping intended parents achieve their goal of a baby, not as possessing a maternal bond with the child. Importantly, surrogate or adoptive children are able to have strong maternal bonds with their non-birth mothers. The maternal relationship is then perhaps not as dependent on the biological (pregnancy and childbirth) basis as its definition suggests. The use of ARTs is also contributing to a growing number of single and same-sex parents. If the maternal bond is as sacred as the status it has been accorded, then what of the children of, for instance, same-sex male partners? (And on that note, what of the children raised solely by their father for various reasons, including maternal death?) Are they all emotionally and cognitively deprived? The answer is no. Perhaps this is because the paternal bond can substitute as a replacement for the maternal bond. Or, perhaps the maternal relationship (or at least elements of this relationship) is not limited to one between a child and the female sex. Returning to the example of non-human animals, let us look for instance at the example of Marmosets – Marmoset fathers lick their newborns as their mother recuperates from the pregnancy, and then feed and carry them. Other examples include male penguins that watch over the fertilised eggs, going months without food, or the Hardhead catfish that carries around fertilised eggs in his mouth also foregoing meals. Facets of these relationships – nurturing, caring, gentleness, and being the prime caregiver – are all qualities attributed to the maternal relationship. When we speak of the maternal relationship we are perhaps referring to a set of traditionally feminine characteristics that are in fact possessable by both male and female. If that is the case, then a maternal bond is thus not necessitated by the relationship between a child and a particular biological sex: female. It is important to clarify that I am not arguing that the maternal relationship does not hold extraordinary meaning. To do so would be to disregard a history of evidence of its importance among humans and non-humans. Most importantly, it would disregard the significant relationship that many women – as the primary caregivers – develop with their children. This is not my intention. My wish is to highlight how the rising use of ARTs is re-shaping our existing framework of reproduction and parenthood. The use of ARTs is providing new sociological evidence that challenges the existing conception of the maternal relationship as having a basis in biology. Whether this will have a positive or negative impact is yet to be seen. *Katie Hammond  is doing a PhD in Sociology at the University of Cambridge, having completed an MPhil in Multi-Disciplinary Gender Studies. This article was first published on the Mapping Maternal Subjectivities, Identities and Ethics blog. Photo credit: Stuart Miles and www.freedigitalphotos.net.