Not all men are created equal and not all men should be there when the baby is born. There are some very real reasons why a man would want to skip baby's delivery (including fear of or sensitivity to blood) but there are also some fake fears, if you will, born in the imagination thanks to Hollywood.

Real Fears
If your partner has real fears and feels uncomfortable around the site of blood you'll likely already know this. Maybe he's the type of guy that faints when he sees someone getting stitches on TV and the idea of a horror movie sends him into a world of panic. If that's the case, talk the process of labor over with him and remind him that he can stand by your head the entire time (for both C-section and vaginal birth). If he sees a bit of blood he can close his eyes, but he's still there.

Fake Fears
If your partner is overworked by fears that are simply not true and based on Hollywood renditions of labor, sit down with your obstetrician and your partner and discuss the realities of labor and delivery. Once he hears the truth about labor you can have a better discussion about his attendance or non-attendance.