Lisette ten Haaf's researches the regulation of reproduction and reproductive biotechnology. Her dissertation, Regulating Non-Existence. The Legal Conceptualisation of the Future Child in the Regulation of Reproduction, deals with the question how we can understand the future, non-conceived child in law, if our interference to protect is result in the prevention of the future child's existence. Various regulatory frameworks (such as the regulation of embryo selection, access to fertility treatments and the bans on reproductive cloning and germ line modification) invoke the interests of the future child as a justification. Ten Haaf criticises this 'best interests of the future child'-construction and offers an alternative theoretical framework is explored that offers us the conceptual and normative tools to adequately address future human life in our normative debates on and the regulation of reproductive biotechnology. For her doctoral thesis ten Haaf was awarded the Goudsmit Award 2025 by the Dutch Society for Health Law.

In addition, Lisette ten Haaf also researches the legal position of unborn life in general, meaning both the future and unborn child. A central question in her research is how the different appearances of unborn life that arise as the result of advances in reproductive technologies and societal developments challenge the existing legal framework. She has written on a variety of topics, including the right to know in the case of MRT, prenatal supervision order and compulsory contraception.

She is also involved in the international research project ‘ART-Equal’ of Norfam (Nordic centre for comparative and international family law) on the role of gender and marital status in the regulation of access to ARTs and parenthood in the context of medically assisted reproduction.