<p>Depending on what he’s looking for, you may want to consider having him take CS 5 Green first semester rather than CS 42. I took this course and loved it. You tackle some very challenging problems, including genome comparisons, RNA folding, phylogenetic tree construction, etc. You get credit for either the CS or Bio core component, and you can go on to take a higher-level course in either CS or Bio to get the other core requirement. It’s a very well-organized introduction to some more advanced topics in CS and python programming (you learn a little more than you would in CS 5 Gold, but not quite as much as Black). CS 42 sort of seems like very rapid introduction to four different programming languages, and some people do wind up dropping it. If he’s looking for a way out of core Bio (all of my friends hated that class), I’d recommend this and following it with CS 60. 60 covers the same material as 42 (plus fast algorithms, Floyd-Warshall, and dynamic programming) but gives you a more solid foundation in the material.</p>