A new Lego tree house kit made with plant-based materials is the latest example of the toy industry’s growing mission to court millennial parents seeking out sustainable toys for their children.

Lego retired its highly detailed Tree House in 2024, and Amazon is only retailer still selling the 3,036-piece model.

Last year, Lego revealed a new type of brick made using a type of polyethylene created with ethanol from sustainably sourced sugarcane. Though it said only a small percentage of total bricks would be ...