Dear Stata Users,

I am dealing with a DHS data set. Here is what it looks like:
ID number Age In months X1
1 6 A
2 3 B
3 2 C
Each child is given with his/her unique ID number. I want to expand my dataset by using child's age in months information. I want to duplicate each observation as follows. However, I could not do it using expand command. How can I do this? Thank you so much !
ID number Age In months X1
1 0 A
1 1 A
1 2 A
1 3 A
1 4 A
1 5 A
1 6 A
2 0 B
2 1 B
2 2 B
2 3 B
3 0 C
3 1 C
3 2 C