Its in the same vein of the axial tilt article here:
http://www.space.com/14295-alien-life-exoplanets-tilt-red-dwarf-stars.html , even the same guy who did that study is involved in this one.
http://www.space.com/14509-alien-planets-planetary-tilt-search-life.htmlI know Fiah already talked about axial tilt, but this is how much the planet is tilted. The effects of obliquity is much better understood. Also, the article should say complex alien life, it doesn't rule out primitive life forms from emerging. After all, we have extremophiles in some of the harshest environments possible on Earth.
It also makes life around red dwarfs that much harder, but if life can arise in such a hostile environment, that shows just how tough life forms can be.
Seems like having a moon to stabilize the planets axial tilt is going to be a major factor in how Earthlike a planet can get.
Also, IMO, a planet with a low axial tilt (less than 5 degrees), probably won't keep life from evolving complex forms, but it might have consequences for evolution, climate, and habitat types, After all, climate change and change of habitats helps drive evolution and diversity on Earth.