PhD defence
Advancing Fertility Preservation: Structural and Functional Insights into the Human Ovary
- H. Cheng
- Date
- Wednesday 11 February 2026
- Time
- Location
-
Academy Building
Rapenburg 73
2311 GJ Leiden
Supervisor(s)
- Prof.dr. S.M. Chuva de Sousa Lopes
Summary
Human fertility preservation is becoming increasingly important as more individuals seek to safeguard their reproductive potential in the context of medical treatments, early-life diagnoses, or gender-affirming care. Yet current in vitro folliculogenesis systems remain limited in their ability to support full oocyte maturation, especially across diverse ovarian tissues. Against this backdrop, my research aims to deepen our understanding of human ovarian biology and develop strategies that more effectively support follicular development for both cisgender and transmasculine individuals.
By comparing child and adult ovarian tissue, I identified key age-related differences in developmental capacity, theca cell support, and late-stage differentiation, revealing why existing culture systems often fall short. I also established a new ovarian classification framework that highlights structural markers linked to follicle viability, providing a practical tool for improving tissue selection.
Comparative culture studies showed that McLaughlin’s medium more robustly supports early folliculogenesis in cryopreserved tissue, while testosterone-exposed samples remain more developmentally limited. Targeting steroidogenic pathways—particularly through CYP19A1 inhibition—partially improved oocyte growth and granulosa cell function in testosterone-exposed tissue, suggesting a promising direction for transmasculine fertility care. Although other agents had minimal impact, observed morphological changes underscore the need to further refine culture conditions.
Together, these findings highlight the need for culture systems that are specifically adapted to the unique biology of different ovarian tissues. This research not only advances scientific understanding but also has important social value: it helps promote more inclusive reproductive healthcare and supports better fertility preservation options for people with diverse gender identities and medical backgrounds.
PhD dissertations
Approximately one week after the defence, PhD dissertations by Leiden PhD students are available digitally through the Leiden Repository, that offers free access to these PhD dissertations. Please note that in some cases a dissertation may be under embargo temporarily and access to its full-text version will only be granted later.
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General information
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