The Fitch & Denenberg target article focuses almost
exclusively on short gestation mammals, which differ substantially
from long-gestation mammals in the timing and type of hormonal
contribution to their sexual differentiation. Conclusions regarding
the role of ovaries in female sexual differentiation may accordingly
apply to only a limited number of species. Specific criticisms of the
organizational effects of hormones stem from an incomplete reading
of the original literature. The mechanisms proposed in this target
article reflect an extension of the principle of hormonal
organization, not a revolutionary restructuring.