Infants are terrible spectators. Blasted object permanence…

I did a french drop for a baby once. After the coin vanished, guess where her eyes went----that's right, my other hand.

Make the baby vanish instead ;-)

"It's in the other hand!!!" said the baby.

I'm a little surprised that a baby did this, but if you only do a FD, or any single vanish, I think you should expect adults to go to the other hand.
That's where a spider vanish (I think that's what its called) can be good. People's mind will naturally go to the previous place they saw the coin. So, that is why many people have said don't do a single sleight as a trick.

John

Another thought, some have tried doing sleights w/a biscuit and their dog. Now that is a real test

... you will get busted

If I was using a french drop as a single vanish, id put that sucker right into nowhere palm. trust me it'll throw people off, especially if your good with using symmetry in your routines. definitely my favorite concealment and I try to use it whenever possible.

Normally after a french drop or whatever I produce another from my pocket, saying, after the vanish, "dern, now I'm down one coin.."

My 19 month old grandson hasn't shown any interest in my magical attempts yet, but when he does I'll be trying out my newly-acquired Secret Servante.

Many years ago a table magician came up to us in a restaurant and tried to show something to my daughter, then around 2 years old. I commented that she was too young to understand the laws of physics, let alone how they could be broken. A little later, though, I stunned her with a simple four-coin assembly ...

Barry

I disagree I do magic for dogs all the time and only do a simple put vanish and they freak out. I had a dog rin away one time

Finger palm vanish for a baby? Not so much. Retention vanish? That got some attention. Problem is, as John said, a single vanish does not a routine make, and it's nigh on impossible to keep a baby's focus for a full routine. (Coin assembly probably would have worked though.)

It's been done, and dogs get fooled too. Although dogs do have highly developed sense of smell, even the "hound" group of hunting dogs is subdivided into sight-hounds and scent-hounds, so some breeds must have even more keen traits than others.

and

Now we just need a breed of sleight-hounds...!