Concentrating on genetics, this paper examines the strength of the links between our biological science -- our biology -- and the particular history which brought that science into being. Would quite different histories have produced roughly the same science? Or, on the contrary, would different histories have produced other, quite different biologies? One emphasis throughout is on the kinds of evidence that might be brought to bear from the actual past in order to assess claims about what might have been. (...) Another emphasis is on the implications for debates on realism and antirealism about genes. (shrink)