Don't underestimate quiet fathers..

(After all, they can work out how machines work, aswell.)
But yeah; it's a good thing these clothes are washed, because it shows acceptance. Well, either that, or they think you've been sneaking a girl in for the lonely nights. And I don't think they believe that, since you didn't find any condoms you haven't bought yourself in the cupboard, now have you?
If they're both silent about it, I think they're waiting for you to take the initiative to sit with them and tell them how you feel. However, I think you could see this as a hint that they're expecting you to do this soon.