This is really cool: even though my sister and I grew up completely apart (we have literally never spent a day living together in the same house) and we were raised and educated in entirely different environments, our handwriting is strikingly similar!
So when I was home some time ago, I saw a report that my sister wrote for her school. I immediately noticed how familiar that handwriting is. That looks like… mine.
So here’s hers and the text that I copied below:

Alright it’s not 100% identical, but still the overall style — the lines, curves, spacing, accents, the mix of cursive and print letters — is all remarkably alike.
As I said earlier, the thing is that we grew up completely apart, almost like two entirely unrelated individuals. My sister was born in Hanoi and has lived her entire life here. I spent the first 5 years of my life in Thái Bình, and then when my mum passed I moved to Hanoi to live with my dad. My sister was then raised by our grandparents. We grew up in different households, went to different schools, socialise in different circles, had completely different career paths. I have literally never spent a day in my life living together in the same house with her.
And yet somehow, despite the divergent life paths, our handwriting managed to end up looking so alike. Genetics must play a factor here — no question about that.
Nature vs Nurture
I used to be a fervent believer in the idea that everyone is born a blank slate, and it is the environment we grow up in that shapes who we are. I believed that genetics, if truly existed, were a marginal factor at best. You know those stories about twins separated at birth and still end up making remarkably similar life choices, down to the car they drive and the partners they choose? I’ve always been incredulous about those.
But well, after growing up and getting to know more people, I’m starting to realise that genetics play a bigger role than I ever thought. The evidence is plentiful, but this is one right here — what an absolutely astounding coincidence that two siblings growing up in completely unrelated environments can produce such identical handwriting patterns!