Oh no.
Flowers and pink.
How ever will I survive.

I'm assuming your nephews are children. And it's normal for kids to assert their gender. But there comes a point where you realize there's not much point to it. There's no objective definition to what's girly or masculine really other than how you pee. It's all based on cultural development. Hell, a hundred years ago, many people considered pink to be the masculine color and blue the feminine color. But that's going on a tangent.

Basically, it boils down to personal perception.