He may have riches and fame but Sir Elton John has admitted son Zachary is going to face a 'very difficult' childhood because of attitudes to their unusual family set up. The 65-year-old star and his civil partner David Furnish, 49, became parents on Christmas Day 2010 to a child conceived using a donor egg and born via a surrogate. But the singer fears his child will struggle with bullies because he works in showbusiness and because of he doesnt 'have a mummy'. Two daddies: Sir Elton John has spoken out about his fears for son Zachary, confessing he's concerned he will be taunted for not having a mother Sir Elton told the Radio Times: Being the child of someone famous is a huge ball and chain around your ankles. It's going to be very difficult. The star revealed that 20-month-old Zachary calls him 'daddy' and Mr Furnish 'papa'. Sperm from both men was mixed to fertilise the chosen egg a process banned in the UK and the child was carried by a surrogate. The whole process is estimated to have cost the couple in excess of $1million (£640,000) but it has not been revealed who the egg donor or surrogate is. He added their unconventional family could cause further problems: At school other children will say, You don't have a mummy. We've come a long way, but there's still homophobia and will be until a new generation of parents don't instill it in their children. Loving father: The Rocket Man believes Zachary will have a 'difficult childhood' Sir Elton insisted he would not push his son to follow him into showbusiness but wanted music to be a 'big part of his life'. He said he has introduced Zachary to Chopin, Mozart and Beethoven - as well as Nellie The Elephant - at a very young age, but that his son was more interested in football and cooking. He has spoken publicly about being a 'hands-on' parent and recently admitted he wished he had not waited so long for parenthood. In a recent interview for ITV1s Daybreak, he commented: I regret a little bit that I didn't do it sooner, but he has changed our lives. Everything is about him now. He's gorgeous, he travels brilliantly, he so loves people, and it makes our lives - he's the icing on the cake. I think it changes everybody. It's the most wonderful thing that you could possibly go through. Sir Elton has also insisted that Zachary needs a sibling. He said: We definitely will have another one. At what stage we don't know, but we definitely will. I don't want him to be an only child. Despite recently reigniting his feud with Madonna by saying that she looked like a 'fairground stripper' and criticising her for being 'horrible' to his son's godmother Lady Gaga, he praised the star. Madonna took the industry by the scruff of the neck, made opportunities for other women, like Gaga and Katy Perry, he said. But he said that 'some (women) aren't good at handling their own careers'. The star, who is presenting a Radio 2 show on the music that inspired him, told the magazine: Dusty Springfield was insecure, like a lot of women singers, including Amy Winehouse. Happy families: Sir Elton John and his longterm partner David Furnish adopted Zachary on Christmas Day, 2010 It's tragic - Back To Black will sound as good in 50 years as it does today. She was one of the greatest, but if someone doesn't want to get well, they won't. Look at Billie Holiday. It's hard for women in this business. Some aren't good at handling their own careers. KD Lang could be a much bigger star but I don't think she wants to be. He also accused Britons of being emotionally 'constipated' after Team GB Olympians were criticised for crying on the medal podium. Sir Elton added: We're constipated, with a train of thought that it's a weakness. Stiff upper lip. Pull yourself together. I hate it. I love to cry. It's a human emotion and very healthy to get all the **** out of you.