My FIL does not have an official diagnosis as he has decided not to pursue it, but it has been indicated to him that he has Aspergers. He also ticks all the boxes. I think when he was younger his "difference" caused him a lot of confusion, now he is secure in himself and his place in the world, and he is very happy, I don't think he feels the need to make it official.
DH definitely has some of the indicators for Aspergers too, though not to the same level as his father. It even shows up in their careers, FIL is a Metallurgist and DH is a Systems Engineer (IT). I think for DH it is a combination of genetics and learned behaviour, as he was raised by his father for the majority of his childhood. MIL could not cope with either FIL or DH so she left them.