I've checked Biology SE on the area51 site and it's been in beta phase for 1196 day as of today. I was wondering when will this site become a full site? What are the requirements?
The "soon" part: Biology is a strong site with great participation, great content, and a great community. As such it's been added to the list of sites we want to graduate.
The "ish" part: There are ten sites ahead of Biology in the queue, and it moves slowly because we currently wait for a custom design to be built before graduating the site. There are sites that have been in the queue since 2013 -- yeesh.
But there's hope!
We are running an experiment on Network Engineering to see how it goes when we graduate a site - bump up the privilege levels, hold elections, all the other fun stuff that comes with graduation - without waiting for a unique design. If this works, graduated sites will still get a special design -- they just won't have to wait until it's ready to graduate.