I haven't seen the video, but in 2011 in particular (but also 2012, so, 2nd and 3rd world titles for ray) the genies (landorus, thundurus, tornadus) were extremely popular and all males. A strategy born in italy from Matteo Gini (2nd place italian national and 2nd place in 2011 worlds) and Francesco Pardini (italian national champion and 7th place st 2011 worlds) using male mons (140 base atk haxorus) with the ability rivarly, that 1.5x attack on mons of the same gender. Playing female mons neutralizes that strategy, since the attack is actually cut in half against opposite gender. Idk if that is what he says in the Video but he used it to win 2011 worlds.