The medic is a vital component of any adventuring party. In fantasy, they are clerics with healing spells or druids with herbal medicines. In contemporary games they can be literal medics, or doctors with field surgery skills. In the future they could be robotic or alien, as long as they have the skills to deal with injured compatriots and make them better.
Usually though, one is enough. After all, concentrating on healing skills means you have to make sacrifices in all the other skills you need to fight monsters and loot treasure!
Luke: Hey everyone!
GM: Hi Corey. Have a good week?
Luke: Who cares?! I can't believe that Darth Vader guy blew up an entire planet!
GM: Just remember, Luke doesn't know that yet.
Luke: Right, yeah.
Obi-Wan: I was just asking Jim about this game that he ran while I was away.
Han: It was awesome. A war epic. Fencing, fighting, revenge, escapes, true love, miracles!
Obi-Wan: Doesn't sound too bad.
R2-D2: Yeah. I was a shell-shocked pilot.
Leia: I played a nurse.
GM: I was another pilot.
C-3PO: I was a doctor. Who didn't want to be a doctor.
Obi-Wan: Mmm. Very subtle.
Luke: Two pilots and two medics?
Han: For some reason they thought they needed lots of speed and healing.