The consequences of TSD on fitness, or reproductive success, are largely unknown. Estrogen can override temperature and induce ovarian differentiation even at masculinizing temperatures. It has been proposed  that temperature acts on genes coding for such steroidogenic enzymesand testing of homologous GSD pathways has provided a genic starting point.
Alex Quinn, a Ph. Sinauer Associates: Massachusetts. In birds and reptiles, estrogen is essential for ovarian development. Recent studies Bergeron et al.
Alex Quinn, a Ph. Recent Activity. Washington: Smithsonian Books, Although other environmental influences can have similar effects, temperature is the most wide-spread factor that alters aromatase activity and sex determination.
Gene Expr Patterns Science In temperature-dependent sex determination, however, it is the environmental temperature during a critical period of embryonic development that determines whether an egg develops as male or female. Download citation.
The Journal of Experimental Zoology. Sources Bull, James. Scientists are still working to understand the evolution of TSD and the implications of climate change for species that exhibit this mechanism of sex determination. Why is sex determined by nest temperatures in many reptiles?
We are finally beginning to understand the mechanisms by which this masterpiece is created. Hermaphrodite Intersex Disorders of sex development Sex reversal. PCBs can act as an estrogen replacement, causing feminization of sex organs in growing reptiles.