what is diffrence between WGM and GM.

The difference is about 200 rating points , or one whole class with the WGM being weaker than the GM . 

Actually WGM is a female WGM and a GM is either a male or a female GM.

WGM is a female grandmaster. 

Mm, i really thought that there was no different rating for women.

I mean why?

I get it when we are talking about physical sports (track and field, basketball, etc) cause there's an obvious advantage for men (muscle mass growth, etc).

But chess? i don't see where's the obvious advantage for men over women at chess.

Well, the brains are different.

The reasoning though was to draw more female players into tournament play.

Have you ever heard of sexual dimorphism?

I have no actual data to prove this....but I am going to go on a limb and say that more men play chess than women. Which is an obvious advantage for men.  However, if we are talking about the top 5% or top 1% or whatever number you want to choose.......the difference in the top players of either gender should be minimal.

I don't think there's enough data supporting the fact that in brains "the bigger, the better"

Brain as a percent of body size would be a more relevant measure.

WRONG!  Judit Polgar is a GM.

If you have a penis, you can't be a WGM, but you don't need one to be a GM.  However, it's a lot harder to get a GM Norm than a WGM Norm because of the opposition you have to face.

Since we are citing wikipedia:

"In the human brain, a difference between sexes was observed in the transcription of the PCDH11X/Y gene pair unique to Homo sapiens.^[70] The relationship between sex differences in the brain and human behavior is a subject of controversy in psychology and society at large.^[71][72] Women on average have a higher percentage of gray matter in comparison to men.^[73][74] However, men have larger brains on average than women, and when adjusted for total brain volume the gray matter differences between sexes is small or nonexistent. Thus, the percentage of gray matter appears to be more related to brain size than it is to sex.^[75][76] Differences in brain physiology between sexes do not necessarily relate to differences in intellect. Haier et al. found in a 2004 study that "men and women apparently achieve similar IQ results with different brain regions, suggesting that there is no singular underlying neuroanatomical structure to general intelligence and that different types of brain designs may manifest equivalent intellectual performance".^[77] (See the sex and intelligence article for more on this subject.)"

https://en.wikipedia.org/wiki/Sexual_dimorphism#Humans

Size of the brain isn't what makes you good at chess (or smart in general) though.

That's not a very convincing argument though.  People can claim social stuff... like countries where the literacy rate for females is 20% and the ones allowed to go to school only go for a few years.

It's not billions of women vs billions of men.  Otherwise yeah, it would be a good argument.

It's a good thing you didn't say "then why are the best women in the world worse than the worse men in the world at everything", you would have a lot people pissed.

Yes, male masters and grandmasters have failed this too.

He kinda has a point on that one though.  It wasn't just a WGM, it was the woman's world champion

Yes, but has a male world champion ever failed this mate ?  

Karpov, I believe?

Just looking on wikipedia, a male 2567 failed it. It's disappointing for sure but Ushenina is not alone.

I know males have failed it.  But none with a world champion title.

It doesn't make her bad as much as it makes the title look bad.