UPDATED BELOW
In portuguese women say
obrigada
and men say obrigado
In thai women say
sawadee ka
and men say sawadee krap
Is there a linguistic term for these gender based distinctions?
How many examples and languages do you know of this?
In theory, you will always know the gender (identity, even!) of the person speaking/writing, what are the effects?
Update:
I feel the need to clarify some things based on the answers. The observation is that some languages are "gendered", in the sense that you speak or write differently based on your gender/sex (identity) - they have (some) gender specific vocabulary. I'm looking for examples of this and arguments on possible implications.