The Birds and The Bees

Boy: Mummy at first you were very sad because you were alone. Then you had children.

MG: Yes, I had you two wonderful children and you make me very happy.

Girl: But mummy will scold us and is angry with us when we are naughty.

MG: Thats right. Mummy will scold you when you are naughty but when you are good mummy is very happy.

Girl: Mummy, can get married then only have children ah. If not married cannot have children?

MG: No. Not married cannot have children. You can have children only after you get married.

Girl: Really ah? Like magic like that? Tell me how?!

MG: Errrr... I'll tell you when you are older.

Girl: Tell me now. I am 7 years old already. When are you going to tell me?

MG: Errr...... when you are 10 years old.

Girl: Afterwards you forget, how?

Alamak! When to talk about the birds and the bees and how?