What's the best interning program to be involved in if you're interested in a biology/medical major at the high school level?

Access to medical school is very competitive. You should spend your non-study time -- your internship time -- experiencing the human parts of health care. That will help you make the case to medical school admissions people that you understand what the practice of medicine is all about.

Try for an internship or volunteer assignment in a hospital or clinic. If you know a doctor or nurse, ask her/him for suggestions about internships / volunteer gigs, and maybe to introduce you.

Children's hospitals always want people to read to and hang out with their patients, for example.

If you can find it, you'll be wise to take an assignment in a hectic part of a health care facility. For example, a messenger for an emergency department on weekend nights might be a great assignment. You'll gain experience of what health care is like under pressure. You may also gain frustration that people make stupid choices that land them in the hospital. Still, the knife and gun club (that's what a doctor friend of mine calls it) is part of the health-care landscape.

If you have a scientific talent, you might look for a gig as a lab assistant in a research lab. If you have a local research university, go to their department offices and check the bulletin boards, or look online.

Have a great career.