Why can't there be a son without a spouse? (Verse 6:101)

> [He is] Originator of the heavens and the earth. **How could He have a > son when He does not have a companion** [i.e., wife] and He created > all things? And He is, of all things, Knowing. ( Al-An'am : 101) The Quran says that the prophet Isa was born without a father. So why does this verse say that without a wife, there can be no son?