If there is a family history of dairy allergy, it's best to wait until 12 months. Usually though cheese and yoghurt are fine from 6 or 7 months. Be wary of cheese though - it is high in salt which is very bad for babies and children. The safe amount per day for babies is very low. Those processed so called children's cheeses are the worst too. You are better off buying tasty cheese like you would for yourself. And give it in small amounts. Easier said than done I know, my boys love cheese and want it all the time!!