Hi,
I thought I would respond to this after reading the last response. 6 months is a fine age to start sippy cups or even regular cups depending on your child. You will need to experiment with many different kinds, I have a ton that I recieved as gifts so that helped from spending a ton of money. what I found with my son is at about 8 months he could drink from a straw and they make spill proof BPA free sippy cups.(munchkins) I currently use the nuby straw sippys because that is what was available for him and there wasn't the BPA concern at that time. I tried switching and he won't use the Munchkin one. Also BPA seems to be a concern more with bottles because of heating and cooling that leaches the BPA, whereas the water, juice etc you put in the cup isn't heated. Straws are better for their teeth too, even if you put milk in there, it has sugar which can cause tooth decay. When he drinks from the straw it goes past the teeth so the milk, juice , etc doesn't really wash over the teeth.
Giving them juice isn't bad, it is what kind of juice, I do my own juicing or on the go there is sugar free juice. (only has natural sugar from the fruit) I wouldn't give any now though. I think I gave juice around 10 months when you don't breastfeed as much. I also dilute it with water, 1/2 and 1/2. (That is what my doctor recommended) My son loves it watered down, he won't drink it full strength. Plus I use fluorinated water since we have well water.
M.