Always Dada and never mama

My son is now 9 months old and he will be 10 months old on the 4th of Sep. His first word was Dada and then it was mama. I so happy when he did say mama because I'm the one that takes care of his little but every day and night.
However...
He has now come to the point to wear everything is Dada and not mama. It's Dada this and Dada that all day. Which its ok cause it is sweet. But at the end of the day I'm want to hear mama once or twice. the only time he says mama is when he is crying or wants me to hold he when he is crying! That drives me up the wall!

My sister came over the other day and was playing with him and he kept saying Dada over and over. She said I want to hear mama. So she starts saying mama over and over to try to get him to do it. And what did that little terd do. He shock his head no every time she said it. LOL Then she said Dada just to see what he would do and he smiled and starts saying it over and over. He is a little terd when it comes to someone wanting him to say mama!!!

I would also like to say Colby took his first steps Sat. Aug .20, 2005. He was not holding on to anything at all. He just stood up and took three little baby steps. He is getting so big it maks me wish he would just stop sometimes. And other times I wish he would just hurry the hell up..LOL
He will be one in two months and a few days. :'(