
The most significant gay subtext was in a story arc in which Francis and his friend Eric (Eric Nenninger) move to Alaska together (because they can't stand to be separated) are mistaken for a gay couple.
Born in 1980, Christopher belongs to a show biz family (his brother Danny starred in That Seventies Show). He began acting at the age of eight, with guest roles on Murphy Brown and Dr. Quinn Medicine Woman.
In 1995 he starred in Cutthroat Island, about the female pirate Morgan (Geena Davis) and her companion Shaw (Matthew Modine) searching for treasure. He played Bowen, her assistant and protege, who displays no heterosexual interest.
In 1997 Christopher returned to the pirate world in Ecce Pirate, about a boy who is kidnapped by pirates and grows up to become their king. Again, no heterosexual interest.
During Malcolm in the Middle, Christopher had some additional buddy-bonding and gay-vague roles, most notably in the "My Generation" episode of the anthology tv series Strange Frequency (2001), about two serial killers of different generations who decide to go into business together.
Of course there were heterosexist roles, too, such as Nice Guys Finish Last (2001), a "teen boy obsessed with girls" short, and Wuthering Heights (2003), which moves the "classic" Victorian novel into a modern-day high school.
I haven't seen much of his post-Malcolm work, but it doesn't look like there's much gay content. As usual, you get to buddy-bond in your teens, before you graduate to "mature" heterosexual romances.
A Scientologist, he might not be a gay ally.