Post by Hanna Engstrom, SLS LLM ’25, CLB student fellow

The European Union’s legal treatment of human embryonic stem cell (hESC) technologies has long stood at the intersection of science, ethics, and law. In 2011, the Court of Justice of the European Union published a major decision in the case Brüstle v. Greenpeace (C-34/10), which has shaped that terrain.

In Brüstle, the Court was asked to interpret Article 6(2)(c) of Directive 98/44/EC, which prohibits the patenting of uses of human embryos for “industrial or commercial purposes.” Dr. Oliver Brüstle sought a patent for a method of creating cells from hESCs. Greenpeace challenged the application, arguing that it violated the Directive’s ethical constraints based on the concept of human dignity. Importantly, while hESCs have significant potential because they can develop into any cell type, obtaining them involves the destruction of the embryo.[1]

The Court responded with a broad interpretation. It held that a “human embryo” includes not just fertilized ova, but also non-fertilized ova if they have the inherent capacity to develop into a human being. The decisive legal criterion was not the process of creation but the developmental potential. For example, this definition catches non-fertilized ova that have been modified to start the development process, such as through parthenogenesis.[2] Most significantly, the Court concluded that any invention requiring the prior destruction of a human embryo was ethically excluded from patentability, even if the destruction occurred before or outside the claimed invention.[3]

The scope is further crystalized in International Stem Cell Corporation (ISCC)[4]. In this case, the Court revisited the scope of Article 6(2)(c), this time focusing on whether parthenogenetically activated ova, egg cells that start developing without being fertilized by sperm, should be classified as “human embryos.” The key question was if these manipulated cells had the inherent capacity to develop into a human being.

Here, the Court refined its approach. It held that parthenogenetically activated ova, do not constitute human embryos under the Directive, provided they lack the capacity for full human development, based on current scientific knowledge.[5] In doing so, the Court introduced a scientific perspective to the legal analysis; only entities with real developmental potential qualify as embryos. This more nuanced reading gave national courts and patent offices’ discretion to look at biological evidence rather than formalistic definitions.

The implications of ISCC have significant effects. The decision opened the door for patenting stem cell technologies derived from entities that resemble embryos but lack full developmental capacity. This shift matters for emerging technologies like in vitro gametogenesis (IVG), which intends to generate a sperm or an egg from skin cells without creating or destroying embryos. As long as IVG applications do not involve embryo creation, they likely fall outside the Brüstle ban.

By distinguishing between entities that are biologically complex and those that has development potential, ISCC offers a more flexible ethical framework that better tracks and reflects scientific understanding and international norms. For Europe, this evolution may help recalibrate the balance between innovation and ethical oversight. It reflects an emerging consensus, that not all embryo-like entities merit identical legal treatment. And not every boundary drawn in 2011 remains suitable for existing and emerging technologies of 2025.

[1] Pera, M. F. et al., Ethical Issues in Stem Cell Research, 7 Cell Stem Cell 85, 86 (2009) (PMC No. 2726839), and Takahashi, K. & Yamanaka, S., Induced Pluripotent Stem Cells in Medicine and Biology, 123 Cell 833, 834 (2015) (PMC No. 4699068).

[2] Case C‑34/10, Oliver Brüstle v. Greenpeace eV, EU:C:2011:649, ¶ 36

[3] Ibid. ¶ 52

[4] Case C‑364/13, International Stem Cell Corporation. v. Comptroller Gen. of Patents, Designs & Trademarks, EU:C:2014:2451 (Dec. 18, 2014).

[5] Ibid. ¶ 28