Yes. 

The number of balrogs has changed in tolkien's mind. In the beginning they were thousands of them, and they were quite weak. For instance when Feanor is surrended by balrogs, Tolkien thought them as far weaker than in later writing, such as the LotR.

In the end he decided that they were seven of them, with the one in the Moria the very last of them.

In the last version, the Balrogs are maiar who were attracted by Morgoth's power and corrupted by him. So they do not reproduce (only Melian among the maiar did), nor were they created by Morgoth.