This is Turner, a 5-year-old boy who's Bean's adoptive son, Alfalfa's brother, and Brussel's grandson. It all started in September, when Alfalfa wanted to have a brother after having an imaginary one for years, but Bean couldn't grow one out of her stomach (after all, Alfalfa was born 34 years prior, though she's eternally 16 years old), so the next best thing for her to do was to adopt. Fortunately, there was a boy at the local hospital (by Sprout Farm) with Epilepsy named Turner, who had lost his parents when they were in a shipwreck (just like Anna and Elsa's parents in Frozen). Feeling sorry for him, Bean decided to adopt him, and he joined the Sprout family in November.
I was having trouble naming him, with Behind the Name coming up with random English boy names. When I asked my sister what I should name him, she suggested Turner because she thought it sounded cool (maybe because he looked like an elementary schoolmate with that name?).