very few of us know what sex we are

It's like saying you can't tell the difference between a cat and a squirrel because they both have a head, four legs, a tail and are furry.

Of course there are numerous ways to tell one's sex without a chromosome test! There are 6500 genetic differences between men and women, OP.

Fortunately for dating, unfortunately for sexism.

See I'm not sure

I have a vagina, I have periods and I have as pair of tits

But I do sometimes wear trousers...And I also like football. I could actually be having male periods, and have a male vagina. Who knows eh?

My cramping uterus shedding its lining and the three children I gave birth to are pretty definitive of my being of the female sex I should think.

I’m pretty sure anyone who has menstruated or conceived a child knows what sex they are.

There’s no doubt in my mind that I am unambiguously female. Still, there’s no accounting for overt stupidity.

When people refer to Gender they are typically referring to the social construct as a label according to stereotypes, i would agree that many people may not know where they fit in on that scale and it may not match with the traditional roles of their sex.

Sex is binary and is determined solely on your reproductive organs.

I don’t think anyone doesn’t know what sex they are unless they’ve never looked in between their legs but I believe some people get confused when their gender and sex don’t ‘match’ and think this means their sex is inaccurate.

People who can't tell their arse from their elbow also struggle with their tits and bollocks

Yup, sadly that about sums it up.

I would ask this person what sex they were and how did they know? I would ask how sex is assigned - if this person replied that the doctor had a look between the legs I would say it was observed.

I would ask how many biological sexes there were and I would ask them to define gender and ask them not to confide or conflate gender with sex and gender identity...and if we got into sexuality I would ask them not to discuss it further as they clearly don't know what they are talking about and as a HCP they should know better.

But then I can say all this as I'm not you OP and I don't know this person but you and I both know they are talking BS.

Ask them what you should look for when choosing a surrogate?

I'd probably say "I'm very sorry for your trouble. I hope you manage to figure it out very soon".

Scary stuff. Si many illnesses present different for men and women, so msny are more common in one or the other and presumably some like ovarian cancer only occur in women. I like the pick two people to make a baby. Maybe pick someone likely to suffer erectile dystfunction. People take men being able to have sex really seriously.

Surely no human has produced both big gametes AND small gametes?

Anyone who knows what sex is knows which one they are.

People who can't tell their arse from their elbow also struggle with their tits and bollocks.

Why are people buying into this stuff?

Possibly because they're not very bright?

(I know what sex I am. I'm the sex that goes through the menopause, so I'm really bloody grumpy after a sleepless night!)

I know what sex I am because I am suffering with menstrual cramps at this very minute. I've had two babies too. I'm confident I'm female.

Why are people buying into this stuff?

Humans are on the whole, stupid followers.

How do I respond to this?

I'd probably just laugh.

Must be a mystery to them how the human race has managed to reproduce...

Sex is observed.
And in 1st world countries if it is ambiguous genetic testing is done.

A young girl who has experienced FGM absolutely knows she's female

Ask them if they know how to make a baby? And what types of humans they would pick to do this.

They must find life very confusing if they can't answer that question correctly.

I’m pretty sure anyone who has menstruated or conceived a child knows what sex they are.

I think we need to let the world continue falling to shit and start over again