How to tell gender of my yellow foot tortoise?

Since it's a baby, it's impossible to know what gender your tortoise is. The tail doesn't get long in males until they're at least 5 inches long. As babies they all look like females. Also the concave bottom shell is not definitive in all tortoises--some species the males have it; others don't. Also many species where the males do have it, some males have it and some don't. I'm not sure if yellow-foots is one of those species that have it or not, but this, like the tail, is something that develops later. You can make a guess from their eye color. Girls often have dark color eyes--brown, yellowish-brown, black, or dark red--and males often have bright color eyes--orange, bright red, yellow, sometimes pinkish. This is true in babies... But again, it's not always definitive--I have seen a tortoise with a short pointy tail, a flat shell, and bright orange eyes, and the only way I know it's a male is he flashed me. He was an adult. But I also saw a male with a long tail and concave shell who had brown eyes, and a female proven because I caught her laying eggs, with red eyes... So point is, you can make a guess, but there's no way to really know until your tortoise gets shows you.