WEINBERGS-RULE AND FACULTATIVE SEX-RATIOS

The author refers to a paper by Coney and Mackey entitled ''Weinberg's Rule versus facultative sex ratio,'' published in Tile Mankind Quarte rly (Vol 37. No. 2) and argues that the number of mechanisms underlyin g variations in mammalian sex ratio at birth (e.g. steroid hormone lev els) is presumably much smaller than the number of variables by which it varies. He suggests that research strategy would dictate investigat ing whether these underlying mechanisms (rather than the ad hoc variab les) operate in conformity with facultative theory.