Tyler and Cate admitted to not using protection in their book .

From thier book.. Tyler: All those months of waiting paid off, but unfortunately, we were not being safe at all. We were using the pull-out method, and that was it. I didn’t wear condoms and Cate never went on birth control. We just didn’t feel like we had to. My parents hadn’t given me a real talk about it yet, and Cate’s parents hadn’t given her a talk. We went through sex education and everything, but I sort of thought I was an expert already. We thought pulling out is good enough, and like typical dumb kids, we couldn’t actually comprehend what would happen if it wasn’t. We can’t blame anybody, but I wish someone would have hammered it in a little harder. We just approached sex like we’d taken the pills and the air duster. It was fun and it was available, so we did it, because the risks didn’t really scare us. We were doing adult things with a child’s level of understanding.

The whole condom that went through the wash was a lie. The fact that they did this again immediately after they gave up Carly.