"Flame Body" ability affects egg hatching.
1. I put a Magmotar in my team
2. I picked up the first egg from the day care man.
3. hatched it. (duh)
TOTAL NUMBER OF STEPS TAKEN TO HATCH CHARMANDER EGG: 2805 steps
4. I took Magmotar out of my team
5. Picked up another egg from the daycare man.
6 Hatched it.
TOTAL NUMBER OF STEPS TAKEN TO HATCH CHARMANDER EGG: 5355 steps
I repeated this whole test again and I still got the same conclusions.
TOTAL NUMBER OF STEPS TAKEN TO HATCH CHARMANDER EGG WITH MAGMOTAR: 2805
TOTAL NUMBER OF STEPS TAKEN TO HATCH CHARMANDER EGG WITHOUT MAGMOTAR: 5355
So my conclusion is that if you have a Pokemon with Flame body in your team, you can hatch eggs much faster.