May 7 (Reuters) - Nintendo Co Ltd is defending its decision to disallow same-sex relationships in its best-selling "Tomodachi Life" mobile game, after fans took to Twitter to urge the Japanese gaming giant to relax that restriction.

According to the fans, married characters in Nintendo's social game gain access to in-game features denied to single ones.

"Nintendo never intended to make any form of social commentary with the launch of Tomodachi Life," the company said in an emailed statement.

"The relationship options in the game represent a whimsical and playful alternate world rather than a real-life simulation. We are a games company first and foremost and our main objective is to create games and consoles for players to enjoy."

Several well-known U.S. games currently allow same-sex relationships, including The Sims and role-playing game Skyrim.

(Reporting by San Francisco newsroom; Editing by Ken Wills)