It is the big question that confronts many fathers shortly after their sons are born - which football team will they support?
Some insist they follow the same team as themselves and in many cases set them up for a lifetime of misery.
But 30-year-old Ian Charters is doing the unthinkable and putting his seven-month-old son Eddie's allegiance up for auction.
The father, from Cheadle, Greater Manchester, is inviting bidders to choose either Manchester City or Manchester United for the youngster - with the proceeds going to charity.
As part of the deal Ian says he will even buy Eddie a shirt and take him to matches.
Eddie was born six weeks premature and spent four weeks recovering at Stockport's Stepping Hill hospital.
And Ian, a Watford fan originally from Hertfordshire, told BBC Sport: "There's no chance he will support my team."
Shortly after birth, Eddie's weight dropped to 3lbs 11oz and he struggled with jaundice and problems with his digestive system. He is now back at the family's home and weighs a healthy 16lbs.
Ian explained: "Eddie was an emergency caesarian section and he was very ill for a couple of weeks. I wanted to do something for the Bliss charity and so I am going to run the London Marathon next year. I set myself a target of £2,500 and was thinking of ways to raise money when this popped into my head."
"Being a Watford fan is not going to happen. My dad supports Dumbarton and I don't care about them. If he's from here he's going to be United or City.
"It's a bit of fun. I'll buy him a shirt and when he's old enough I'll take him to a match. I'll make sure he supports them. It's mostly City fans where we live but it's 50/50 at work. Everyone thinks it's a good idea."
The auction will start on Thursday evening. The listing on auction website eBay states: "I live in Greater Manchester, but originally come from down south so I have no affiliation with either of the Manchester clubs.
"I'll be fighting a losing battle trying to get my son to support my team (Watford). Frankly, I wouldn't want to inflict that on the poor child anyway."
City and United clash for the first time this season at the Etihad Stadium on 2 November.