In the last few decades, the study of maternal effects, as being strongly suggested by its name, has been substantially investigated from the perspective of mothers in terms of mechanisms and its evolutionary consequences. In addition, when it comes to the maternal effects on the offspring, the studies have been and still are more often than not focusing on the post-natal stage. However, recently, several studies have suggested that embryos are also playing an active and important role that may potentially induce a mother-offspring conflict by heavily converting maternal androgens to other hormones. Yet, this also has led to many unknowns. Therefore, in this thesis, I focused on the role of the embryo in determining its own development under the influence of the mother. In particular, I explored 3 important unknowns about the embryonic metabolism of maternal androgens which are: 1) to what extent do embryos can affect the hormonal environment they are exposed to during early development, 2) how does such a hormonal environment affect their prenatal development, and 3) are embryos able to control their early hormonal environment depending on the context in which they develop.