I just learned this today, is it true?

Although on the rare occasion a calico cat does turn out to be male because something went wrong with sex chromosomes, it's usually sterile.

True. Usually the sterile cat will have two X chromosomes AND a Y chromosome, making a calico or tortoiseshell male. And since their sex chromosomes are screwy, they're almost always infertile.

I think this post is only referring to calicos and tortoiseshells. Besides, isn't the brown on Siamese cats and Ragdolls just a transition color and not a "proper" color?

Not really, depending on the pattern. The post says "only female cats have 3 colors", which is why I clarified.

Males can be calico, but it's very rare and they're almost always sterile.

waaaaaaah my dylan is a calico and a male and waaaaaah

How's Dylan? :v

My cat was orange and female. So.. no.

3/4 ginger cats are male. The orange gene is on the X chromosome and a male needs only one to be orange. Female cats, however, need two copies to be orange so they're more uncommon.

so ginger hair is recessive in cats?

It's a bit more complicated than that, because colour is sex-linked in cats. Since the gene is on the X chromosome, males only get one copy of a colour gene while females get two, so males will just be the colour of their one gene while females can be mixed. But yeah, for a female cat to be pure ginger she needs the orange gene on both her sex chromosomes