Excessive Radiation (A Pair Of Classic Sci-Fi Stories)

Radiation Can Really Mess Things Up, is a classic Sci-Fi story about what happens when you aren't monitoring the site of a nuclear disaster like Chernobyl, quite closely enough. We Must Increase Our Bust, is about a woman who feels she is perpetually skinny, no matter how hard she tries to bulk up at the gym. After she runs out of gas on the way home, a man who she recognizes from the gym, stops and helps.
She is attracted to him even though he is a bit overweight but when she invites him into her house, their sexual feelings intensify when she feels an immediate attraction to him, and after that, things start to change in a most interesting way.