I imagine that most parents might first think that kids and plants or kids and statues, or worse kids with plants AND statues, is a recipe for disaster. The "Niki in the Garden" exhibit from 2007 featured very large, vibrant mosaic pieces of animals, dancing women, people, and mythical creatures (many of which you were invited to climb on, sit on, or touch).
But even when there is no special event, it is such a rich, wonderful place to introduce children to gardening. I wish I had more pictures of my kids just enjoying the garden. They can spend nearly an hour exploring in the fern room alone. I recommend going on a week day and you'll have the entire place to yourself. It's heaven.