There are two southern entrances to Lost Woods proper. Take the eastern one; there's a large boulder blocking the path. Lift it to discover a baby underneath.
Look south between the two entrances to spot this one attached to a wall.
Now head up the western path and enter the woods proper. Follow the path to reach these two puffs of grass. Slice up them up to discover another baby.
Now head to the northwest corner of the woods. Here you'll find a skull surrounded by grass; there's a baby inside this strange arrangement.
Head to the destroyed house just east of the woods (the equivalent of Rosso's house in Hyrule). Look south and use a Pegasus Boots charge into the tree here; you'll shake loose a baby.
Head south to find these trees arranged into a V-pattern. Slice up the purple flowers in the middle to reveal another baby.
There's another baby in this direction, just a bit further south. Enter the pit to find it attached to a wall.
Now move west. Just beyond the gateway for Thieves' Town, you can see this baby attached to a cliff wall.
There's a large boulder just outside of the Lorule Sanctuary. Underneath is a baby.
The next baby is attached to the wall north of the Graveyard proper.
Follow this region until it wraps southeast. Use a Pegasus Boots charge on the tree here to shake loose a baby.
As you ascend, stop at this ledge and drop down. Bust up the skull to free a baby.
Take a left from the Treacherous Tower. Use the Hammer to clear the pegs, then move to the western edge of the platform. Lift the boulder here to reveal a baby.
Head to the incomplete bridge just south of Treacherous Tower. Lift the boulders here to reveal another baby.
This baby is found in the exact same place as Baby #26, just transposed to Lorule. Break up the skull on this ledge to find it.
This is found high on a cliff wall in the extreme southeast corner of the mountain. Merge from the higher ledges to the north to reach it.
The last baby here is just "chilling" on a rock face behind the Ice Ruins.