Periods are Les bas de soie noire (1981) xxx movienormal, but kids pointing them out in their sketches is something else.

Australian woman Penny Rohleder shared a photo of her son's drawing on the Facebook page of blogger Constance Hall on Jul. 25, which well, says it all.

"I don't know whether to be proud or embarrassed that my 5 year old son knows this," Rohleder wrote.

"Julian drew a family portrait. I said 'What's that red bit on me?' And he replied, real casual, 'That's your period.'"

Well, at least he knows.

To give further context, Rohleder revealed she had pulmonary embolism in October 2016, and was put on blood thinning treatment which makes her periods "very, very bad," she explained to the Daily Mail.

"Jules was super concerned, but he knows about periods -- kids follow you to the toilet every chance they get -- and so he just kept asking me if I was ok," she told the news outlet.

OK, that's pretty sweet. And what's more, Julian understands how an everyday bodily function works. Nice one.