My sisters hamster always comes to her and mine runs away from me. Why? Mine is a male and hers is a female, we house them seperatly and have owned them for 3 days.

In most of the rodent species, the female is a lot more trusting and risky then the male is, but if the male is only running away rather than trying to nible at you, then it is a good thing. Try to ignore it and leaving it alone, it be might bring him coming to you instead.

And every animial has its own nature, are you and your sister the same, NO. Many hamsters don't like people as much and just "put up with them" but you want to take your time and it should get used to you

One trick you do with rats is to sit cross legged on the floor and drape a blanket over your head and body so it's nice and dark.
You them let the rat(hamster) crawl over your legs.
This gets them used to your scent and being touched, but they feel nice and secure being in a dark space.

You can also try this in a small (SECURE) room like a bathroom with the lights off, just let the hammy run around the room and stay nice and still. It gets them used to you being there and they get used to your scent.

Hamsters really don't like to be held. Many of them will put up with it, over time, but it's not something they enjoy. It's something they tolerate, or get used to.

You've had the hamsters for 3 days. That's not nearly enough time to determine whether your hamster "likes" you or not.

Give it time. Let the hamster come to you. Offer treats, pick a time when the hamster is more accepting of human companionship. Be patient.

That's all you can do. It either works, or it doesn't. Welcome to the reality of owning a hamster.