VERY FEW schools will say something against summer science courses. VERY FEW.
On the other hand, many schools have no problem with summer courses and in fact, if you don't have the prereqs finished by the time they interview you, they will tell you to get them done prior to matriculation. Implying you can apply without having the prereqs done, get into places (following interview or whatever), take the prereqs the summer prior to matriculation, and get in toastily. Be sure if you are taking the prereqs prior to the summer of matriculation that you email the Dean/Ast. Dean the courses you're taking to see if they qualify. Good luck.