normal on a seedling.. don't worry about it.. you'll see that split and woodier looking.. green stem will start to push through...like the incredible hulk.
Edit:.. get them into separate containers if you still can.. IF you can.. the roots are likely already tangled..
I'd start a thread and ask if people have or suggest doing it.. I have hydro set up, and don't know what pulling them apart would do.. and you will hopefully get some help.