Can mollies cross breed?

okay so i'm sure that my molly fish is a female, and my male black skirt tetra keeps chasing him around. he is not hurting the molly, and the molly isn't bothered by this. i heard this was a mating behavior of fish, but i'm pretty sure mollies and any kind of tetra cannot crossbreed. i've heard of platies and mollies being able to crossbreed (i also have a couple platies in my tank), but not mollies and black skirt tetras. So is this behavior between the molly and black skirt tetra mating behavior or something else?