Social egg freezing is a fertility preservation strategy which enables women to preserve a number of healthy unfertilised eggs for potential future use when faced with the threat of age-related fertility decline. The overall aim of this thesis was to explore how women understand, construct and experience social egg freezing in the context of debates surrounding reproductive ‘choice’ and ‘delayed motherhood’. The study sought to provide insights into how women perceive the risks and benefits of social egg freezing, how it relates to their discourses of parenthood and their future reproductive intentions as well as how the ‘medical’ encounter in egg freezing is experienced. The thesis draws on Layder’s theory of social domains, selectively focusing on the domains of contextual resources, situated activity, and psychobiography to explore the macro and micro level aspects of social egg freezing (Layder 2006). Consistent with this theoretical framework, the study utilised a multi-method approach: a content and critical discourse analysis of UK newspaper articles on egg freezing, a demographic questionnaire, and semi-structured interviews with 31 users of egg freezing technology. ‘Career reasons’ were presented as the dominant motivation for social egg freezing in newspaper reports. Highly gendered messages interwoven with discourses of blame and failure were identified throughout the newspaper sample alongside moralising discourses calling for women to act responsibly towards their fertility. Emotive language and specific lexical choices were central in constructing discourses about motherhood and reproductive timing which largely excluded a consideration of the structural, relational and ideological factors which influence reproductive timing and reproductive ‘choice’. The demographic profile of interview participants was similar to that found in existing quantitative studies of social egg freezing. Participants were predominantly single, highly educated women in professional careers, with an average age of 37 at the time of undergoing egg freezing. Egg freezing was constructed by participants in relation to a particular biological project and sense of self. Motherhood was something they wanted to experience at the ‘right time’ with the ‘right partner’. The right time for motherhood was related to the feeling of ‘being ready’, which was often linked to the acquisition of certain preconditions for parenthood. The ‘right’ partner was constructed as someone who reflected certain cultural ideals often associated with ‘new fatherhood’. The absence of such a partner indicated that it was the wrong time to pursue motherhood and thus led women to pursue social egg freezing. Many participants reported that a particular issue or event had acted as a critical factor leading them to undergo egg freezing. These included the breakdown of a relationship or the diagnosis of a health or fertility related problem, thus blurring the conceptual distinction between medical and social egg freezing. Through the use of Layder’s theory of social domains and concepts of neoliberalism and biomedicalisation, the thesis argues that women’s engagement with this technology is influenced by both macro and micro sociological factors including ideologies of parenthood, an individual’s social location, relationships with intimate partners and men’s fathering intentions. When faced with the ‘risk knowledge’ of their declining ovarian reserve, the female users of this technology can be seen as enacting ‘reproductive responsibility’ commensurate with neoliberal values of responsibility, self-actualisation and self-determined action in pursuit of a particular construction of motherhood. This theorisation provides a challenge to current understandings around delayed motherhood and suggests that women’s use of social egg freezing should not be seen simply as the outcome of women’s ‘choice’, but as a process involving a complex interrelation of discourses which contextualises decision making in the reproductive realm. This research has implications for practitioners, regulators, users and potential users of this technology, as well as for researchers concerned with questions of reproductive choice, delayed motherhood and reproductive timing.

Indiana University-Purdue University Indianapolis (IUPUI) / Recent genome-wide association studies (GWAS) have identified many common genetic variants that are associated with women’s reproductive timing characteristics including ages at menarche and at natural menopause. However, the associations of these variants with other human health related phenotypes such as blood pressure, cancer, diabetes, obesity, and body height growth have not been well studied. No published studies to our knowledge have directly assessed the genetic influence of reproductive timing related variants on the aforementioned common traits. A better understanding of pleiotropic effects of these variants is important because it will help elucidate the precise mechanisms of common traits/diseases such as hypertension which have not been fully understood so far, and give clues for developing better solutions for disease prevention and treatment. We, therefore, conducted three studies to explore genetic variant effects on blood pressure and body height growth. In the first study, we analyzed data from a local cohort of 601 healthy adolescents from Indianapolis schools. Mixed effect model analysis revealed that 11 reproductive related single nucleotide polymorphisms (SNPs) were significantly associated with blood pressure in the study subjects. In order to assess if these genetic effects extended to the adult blood pressure, we performed the second study to investigate the genetic effect on blood pressure in adults. We used the summary statistics obtained from the two large international GWAS consortia, the Blood Pressure Consortium and the ReproGen Consortium. Bivariate analyses showed that more than 100 SNPs were associated with both blood pressure and reproductive timing. As the blood pressure development is closely related to somatic growth, we conducted the third study to exam the genetic effect of reproductive-timing related variants on the linear growth from the aforementioned local cohort. We identified 8 genetic variants significantly associated with the catch-up of linear growth in the study subjects. In conclusion, these three studies collectively provided evidence in support of the pleiotropic effects of the reproductive timing variants, suggesting the common genetic basis underlying the correlated traits. Future research is needed to validate the findings. / 2 years

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Environmental gradients can help shed light on the evolution of life history strategies such as parental investment. Parental investment is crucial for the fitness of many species. In this thesis, I examine reproductive investment dynamics in the Eurasian blue tit (Cyanistes caeruleus) in the French Pyrenees and assess potential differences in reproductive measures across an altitudinal gradient that creates variation in environmental “harshness”. Further, I investigate fine-scale aspects of bi-parental care, such as investment tactics in current reproduction, and sex differences in contributions to offspring care. To do so, I used a mixture of observational and experimental data, collected over a total of six breeding seasons from over 500 blue tits nests. I showed that breeding conditions are “harsher” due to colder temperatures with increasing elevation, leading to changes in reproductive timing and output. I found that increasing altitude leads to decreased hatching success. Nevertheless, clutch size and brood mortality is comparable across the gradient. A shift to a lower, but qualitatively comparable reproductive output may be part of a slower “pace of life” strategies pursued at high relative to low altitudes. From experimental data, I also found that parental investment is positively linked across different phases within one reproductive attempt. Finally, in line with theory, a temporary brood manipulation revealed that parents balance the benefits and costs of reproduction by partially compensating for changes in brood size. Parents also responded in similar ways to brood size. Overall, the findings presented in this thesis highlight the importance of mechanisms to fine-tune reproduction to maximise reproductive fitness. I suggest that initial reproductive decisions such as timing and amount of offspring produced heavily shape the success of a reproductive attempt. These results have implications for current versus future reproductive trade-offs in life history theory, in particular for short-lived species.