Hair genetics from best to worst:
Ken Shamrock (Norwood 1 going strong in his mid 50s with very little diffused thinning)
Vitor Belfort (Norwood 2 early 40s, still very solid hairline with no visible breach at the vertex)
Chuck Liddell (Norwood 3 in late 40s, but very hard to tell with his mohawk style which deserves bonus points. Vertex has not been breached)
Tito Ortiz (struggling with hair loss in both temple and vertex areas since his late 30s, tried to hide it by bleaching his hair and having buzz cuts, finally shaved it off)
Randy Couture (visibly balding since his early 20s)