Even before they were three years old, your child is likely to have referred to themselves as a boy or a girl, having noticed their physical differences around the age of two.

And by their fourth birthday, they will have a strong sense of gender identity.

So this year of their life is one in which they are learning and mimicking gender role behaviour.

They'll be aware of things girls do and things boys do, but this may not always conform to what you might expect.

READ NEXT: How to support a child through a gender transition.

Be open-minded and your kids will approach their own identity and others' in the same way.

Around this age, girls will often gravitate to "girly" activities and toys such as dolls and nurturing role play, while boys will turn towards active play like trucks and action figures.

While there's no reason to discourage kids from what they're naturally drawn to, it's still important to give them options to explore in games and sports, so throw some gender-neutral toys into the mix.

WATCH: Mum loses her mind over gender reveal. Story continues after video …

As parents, you can help them be open-minded about gender roles.

Dad can play dress-ups and host tea parties, just like Mum can fight imaginary ninjas!

For some children, the link between their biological sex and gender identity is not so clear – and it doesn't have to be at this age.

Loads of little boys like to pop on a tutu or pretend to be a princess, but it doesn't mean they are set for a gender transition.

Be open-minded and your kids will approach their own identity and those of others children in the same way.