4.1 Vtg phosphoprotein patterns
We found no evidence of Vtg in male turtles, suggesting that this population was not exposed to environmental estrogenic endocrine disruptions seen in many other exothermic species.
Considering this, and that female’s follicles enlarge when reproductively active animals begin vitellogeninesis, it might appear plausible to use Vtg sampling as a viable method for determining if a sexually ambiguous adult turtle is female.
However, timing of follicular enlargement often depends on species and geographic location, so samples taken too early or too late in the season may lead to incorrect conclusions.