Sex symbols ancient and modern: their origins and iconography on the pedigree -- Schott 331 (7531): 1509 -- BMJ

Sex symbols ancient and modern: their origins and iconography on the pedigree -- Schott 331 (7531): 1509 -- BMJ: "Sex symbols on pedigrees were illustrated quite differently 150 years ago. What brought about the change?
Nowadays no scientific paper on genetics involving an extensive family history would be complete without depiction of the pedigree, on which squares represent the male members of the family and circles represent the females. But it was not always so, and a century ago ancient and modern symbols vied with each other in the genetic and eugenic literature.1 The origin and iconography of these symbols, one pair with a history dating back many centuries, the other pair originating in 1845, are the subjects of this discussion. "/.../