RESUMO
The correct explanation for the freemartin phenotype in the female twin of a female-male pair in cattle was first reported by Tandler and Keller (1911. Deutsche Tierärzt Wochenschr 19:148-149). This same explanation for the freemartin was independently discovered by Lillie (1916. Science 43:611-613). Today both set of scientists are given credit for this discovery; it is the basis for much of the subsequent work on the developmental basis for sex differentiation in vertebrates. Even though Lillie published after Keller and Tandler, he gets credit for this discovery because: (1) Keller and Tandler published in a veterinary journal and as a consequence their work was not disseminated as broadly throughout the larger scientific community; this problem was compounded by the fact that their definitive 1916 paper was published under wartime conditions during World War I, and (2) Lillie was an influential scientist with a group of graduate students who could elaborate on and extend his work; they published a number of papers on the freemartin. At some point while Lillie was doing his initial work on the freemartin he may have become aware that Keller and Tandler were also working on the freemartin problem; this information may have shaped his decision on when to publish.
