It is generally not advised to install wood flooring in bathrooms as wood tends to expand and contract with water exposure and drying, and over time, they can warp and become unstable. As a natural material, mold also likes to grow on damp wood. If you have your heart set on wood, look at engineered hardwood planks. These are specially made by layering thin cross-sections of wood at angles to make them resistant to moisture warping. However, it is a good idea to dehumidify the bathroom with these floors to avoid mold development.