The Old Mc title can be unlocked by completing the player-owned farm breeding log. In the event more animals are added to player-owned farm, the title will be locked again until the player manages to breed all (new) animal breeds.
Unlocking the title will prompt the following message:
You have unlocked the title 'Old Mc'.
You'll need to maintain this title as and when more animals are added to the player-owned farm breeding log.
This title changes according to the language of the server on which RuneScape is played, as shown below: