The inclusion of 4-year-old Michael Jackson impersonator Kayim-Ali Jaffer in this year's series has drawn comment from the leading children's charity Kidscape.
Jaffer is thought to have recently wowed judges Simon Cowell, Piers Morgan and Amanda Holden at the audition stages and has since been tipped as a "shoe-in" for the semi-finals.
However, Kidscape director Claude Knights told the Daily Mail: "He may be talented but you have to remember that this little boy has only been talking for a few years - now he is performing in front of a huge audience and will be seen by millions.
"Unless he wins he is also going to have to deal with rejection. I am not sure it is fair to have someone so young compete like that. It seems that the age at which people are appearing on these programmes is getting younger. What next? 2-year-olds on stage and then being voted on or off Britain's Got Talent?"
Controversy over young competitors on the ITV1 series first began last year when child acts like Hollie Steel and Natalie Okri broke down in tears on the live shows.
However, panellists Morgan and Holden have always insisted that children should be allowed to take part.