There are ways to decorate a shared bedroom so that the space looks unified and there's still some room for personal expression. Check out these pictures:
For many families, having a crib and a twin bed in the same room is a practical solution. Use a bright but complementary color on the bed to distinguish it from the rest of the room while still tying the look together.
Bunk beds are perfect for saving space, and they can be incredibly versatile. In this case, choosing a wall color that everyone can agree on is paramount. Then, keep the beds a basic, neutral color like white and accessorize with accent colors that aren't gender specific.
Another good trick is to keep the wall color neutral, and use the beds as statement pieces. Notice that by following the same style of beds and bedding, they could personalize the colors and patterns more while still maintaining unity.
Wall decals aren't gender specific, and they can tie together two spaces that aren't identical. For example, if there was another bed in this room with similar colors but different patterns/styles, the look would still come together nicely.
This room is another example of the way wall colors and embellishments can unify a room. The styles of the beds are identical, but the colors are not, and they all create a complete look.
Images via Flikr