Professor Green thinks he's too old to become a dad.

The 31-year-old rapper, who's married to reality TV star Millie Mackintosh, 26, has claimed it's already ''too late'' for him to become a father.

Speaking at the launch of his autobiography, 'Lucky', he said: ''People used to get married at 20 and have a baby at 21.

''That's better than leaving it too late like now.''

Pro Green's remarks come shortly after he revealed that he and his wife occasionally engage in ''heated arguments'', but thinks such tensions are a natural part of married life.

The rapper - whose real name is Stephen Manderson - shared: ''We have got into heated arguments in the past, but everyone gets heated at times! And we do kiss and make up ... a lot! We are f**king married! ''

The 'Lullaby' hitmaker also claimed they could not be happier, despite rumours to the contrary.

He said: ''Millie and I argue over her not turning the lights off, me leaving my boxers on the floor! Even though it might get heated, it's healthy.

''We spend out whole time taking the mickey out of each other and we love it! It is never mean, it is just a giggle and if it wasn't then I wouldn't be with her! Your looks are going to go but your sense of humour always stays!''