Olivia Bee for The New York Times “First base, second base, third base, home run,” Al Vernacchio ticked off the classic baseball terms for sex acts. His goal was to prompt the students in Sexuality and Society — an elective for seniors at the private Friends’ Central School on Philadelphia’s…

A rendering, at right, of what a healthier breed of bulldog might look like, based on input from veterinarians: A) short snout made longer; B) skin folds reduced; C) body made leaner; D) tail elongated; E) hips widened. Photograph by Andrew Bettles for The New York Times. Photo illustration, right,…