Why do they never have sons?

This morning, when I first heard someone say the title The Gerbil Farmer's Daughter, I thought, Ha! Someone has finally written a book that parodies the "Female Relatives of Men with Interesting-Sounding Occupations" publishing trend and title formula! (and Damn, I should've done it first!).

But no. The Gerbil Farmer's Daughter is a memoir by a gerbil farmer's daughter.

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