Sure. And you can have sane policies to deal with this. One of which is to disclose your relationship to HR so that provisions could be made to mitigate these k

Sure. And you can have sane policies to deal with this. One of which is to disclose your relationship to HR so that provisions could be made to mitigate these kinds of issues or to move the manager or subordinate to another team. If you don't disclose a relationship with a subordinate, you should be held accountable for that.