Why does prenatal exposure to diethylstilbestrol increase masculine behaviour if it is an oestrogen?

Question

From a study:

In a wide range of non-human species, hormones exert powerful influences on behavior during early critical periods when testosterone levels are elevated in males. During these periods, administration of testosterone or its metabolites (including estrogen) to females increases male-typical behavior and decreases female-typical behavior (Goy; Phoenix; Beach; Beatty and Goy)

Why, if diethylstibestrol is a synthetic oestrogen, does it increase androgens? Don't oestrogens have opposite effects to testosterones?

Answer 1

Based on your reference quote, it seems to suggest that _any_ prenatal exposure of steroid based hormones increases male-typical behaviour. The fact that the post-natal effects of having a higher oestrogen concentration than testosterone has an "opposite" (female-typical) effect is a red herring.