Do you consider in laws as incest?

There are different perceptions of what incest is. For some people it’s the taboo of crossing traditional relationship boundaries. A lot of those people would lump in-laws in too.

For others it’s only about shared DNA. A lot of those people would exclude in-laws.

For what it’s worth, the actual definition of incest is explicitly about the shared DNA. Nobody perceives the world through definitions though.