Why do mosquitos keep biting me?

Mosquitoes seem to prefer certain people over others. I've seen it many times. You probably know someone who says "Mosquitos love me!" What's up with this?

My wife and I will be outside on a summer evening and she'll get eaten alive, while I'm standing there without a single bite. What's going on? She is Filipino and I am of germanic descent. Does that have anything to do with it? I think some person,s having suger level higher have sweet blood, which attracts mosquetoes more than a person having lower suger level and have tasteless blood.