Gender treatment in nonfiction is something writers have struggled with for decades now. On occasion, it has resulted in sentence construction that would do Rube Goldberg proud.
As writers dance around this particular thorn, two of their many partners are “his or her” and arguably the worst four characters ever put on a page: s/he.
Further, to avoid the wrath of those who would accuse authors of sexist writing, some writers include in their prefaces disclaimers such as, “All generic male references are intended to refer to females as well, and vice versa.”
From 2002 to 2007, I worked for an education company that developed a solution to this problem. The company's product is a complete online curriculum (every subject, K–12) for home schooling. The workaround to the “Dick or Jane” problem was to simply alternate male and female forms from lesson to lesson. It worked for both the curriculum developers and the customers, not to mention the editors.
I had not seen that style used again until this week, when I received a new book manuscript to edit. The author didn’t even bother with a disclaimer; he simply alternates the male and female from chapter to chapter.
This approach perfectly illustrates the maxim that when considering all possible options, the simplest one usually is best.