If you were walking down the sidewalk and saw a visibly pregnant woman leaning against a building with some friends chain smoking, you would be concerned. Depending on what kind of person you are, you might even say something to her. But if a (male) buddy of yours did the same, you wouldn't feel the same way. When a woman is pregnant, she's expected to eat healthy and exercise for the health of herself, but most notably for the baby. Should men do the same, for the baby?
A recent report in Nature suggests that he should, especcially if he plans on having daughters. Because I'm phlogging, I don't know how to link to things, but trust me! Or check Nature. So they fed male rats a high-fat diet, let them breed, and looked at the metabolic profiles of their offspring. They found that in the fat rats' daughters, they should diabetes-related symptoms, such as insulin insensitivity and reduced pancreatic cell function. Because of their fat dads.
I recently read another study discussing the effect on sperm of men smoking cigarettes. Because there is one. Ah, the terrifying field of epigenetics. I'm just now discovering this Dad Effect. I think I'm representative of the majority when I say I had never thought about this before. Why is that? I don't expect all the details of paternal epigenetic effects to be common knowledge, but at least the idea that they EXIST should be.