The Annals of Science: Are Numbers Gendered?

According to a new study by Northwestern University psychologist Galen Bodenhausen and marketing Ph.D. student James Wilkie, the answer is apparently yes. The abstract from the Journal of Experimental Psychology reports:

We examined the possibility that nonsocial, highly generic concepts are gendered. Specifically, we investigated the gender connotations of Arabic numerals. Across several experiments, we show that the number 1 and other odd numbers are associated with masculinity, whereas the number 2 and other even numbers are associated with femininity, in ways that influence judgments of stimuli arbitrarily paired with numerical cues; specifically, babies' faces and foreign names were more likely to be judged as "male" when paired with odd versus even numbers. The power of logically irrelevant numerical stimuli to connote masculinity or femininity reflects the pervasiveness of gender as a social scaffolding for generating understandings of abstract concepts.

The numeral 1 I kind of get, but what is so masculine about the curves in the numeral 3?