This cartoon by Adams from The Telegraph relates to news that under the UK government's equal marriage legislation, due to be published in late January, the Church of England will be banned from offering same-sex marriages.
The cartoon shows Noah standing on the deck of the C of E (Church of England) ark. Two unicorns are on an island surrounded by the rising flood water. Noah exclaims, 'Gay?!!'
We can assume that the unicorns have just told Noah that they are gay, which is why he did not allow them on the ark, which is why there are no unicorns today! Except in Harry Potter. And North Korea.
In the bible, Noah's Ark is the vessel with which the Patriarch Noah saves himself, his family, and a remnant of all the world's animals when God decides to destroy the world with a great Flood because of mankind's evil deeds.