Is it normal for siblings to see each other naked?

Anonymous
I have two sisters. One is 3 years older than me and one 5 years younger. I am a fairly modest guy. But my older sister gives no shit about modesty when we both are alone. It became a common thing for her, as soon as our parents leave for some party or function, she goes around topless. If I nag her, her only comeback is " This is the only time I can do this. And why do you care?" cue in swinging boobs. We are very close. We practically share a room (only a wooden partition with a door separate are room).
On the other hand my younger sister is modest. Always primed up. But I have caught her peeking around when I am changing clothes and write it of as "curiosity".

But this got me thinking if is it normal thing in siblings.
Is it normal for siblings to see each other naked?
17 Opinion