Unless the CPS has a warrant to talk to the child or a warrant to take your child then no you do not have to let CPS talk to your child.
In fact if the CPS has no warrant you should never let the CPS talk to your child especially without you being there as the CPS can get the child to say things against you even though the child doesn't mean to say something against you.
The CPS will want to twist the child's words.
If you do let the CPS talk to the child always do it outside and stand right there with them and never let the CPS intimidate you.
You have every right to be with your child while he/she is being questioned by the CPS.
For CPS Child Protective Services to take a child or children away from your home they need sufficient evidence to remove the child from your home and from your custody.
A CPS worker cannot just show up at your house without a warrant and then take the child from you.
Some CPS workers will show up with police and use the police to intimidate the parents so that they let them inside the house.
Remember though that the police officer just shows up with the CPS worker for the CPS workers protection and is not there to force entry unless they have a warrant signed by a judge.
So never let the CPS inside your home without a warrant because once you do they can and will do whatever it takes to find something to remove your child over.
It could be as simple as some dirt on your floor or your house not picked up properly.
Also never let your child go talk to the CPS worker alone because they can get the child to say things they shouldn't and when they record what the child is saying they can edit that recording and try to make it sound like the child said something against you.
Now if you're actually abusing the child in the CPS view or the polices view then they can take the child without a warrant.
But other than that if they do not have a warrant to enter your home or a warrant to take the child from you then no they cannot take your child from you without the warrant.