Who do you save?

This is purely a hypothetical situation, I'm just curious what people would do. It's a bit morbid so I'd suggest you stop reading now if that's not your cup of tea.

Here's the situation:

You're on a cliff and two people are hanging off of it. No one else is nearby and you cannot call for help in time. Neither are able to pull themselves up on their own and are losing their grip. They will most definitely fall off and die if you do not pull them up. There is definitely not enough time to save both, no matter what you do only ONE will survive.

They are both the same age, race, and weight. You can physically pull up both of them. You don't know anything about them and there isn't enough time to ask them anything. Both are wearing a plain black shirt and jeans. Nothing is there to indicate who they are or anything about them. They are both strangers to you. One is a young boy and the other is a young girl. Who do you save?