Hi, I'm far from an expert, but I've had a number of my photos rejected and learned a lot from the critiques on these forums. The only thing I can see is that the faces aren't completely sharp, especially the youngster's. They really want the eyes in particular to be crystal clear. Hope this helps. I'm sure you will get more and better advice from the experts that haunt these forums. 🙂
The photo looks to be taken with a smartphone - because of this when enlarged, the photo shows signs of pixelation:
Because of the camera's noise processing, it has also smudged the pixels a bit. Enlarge to 100% and you'll see what I mean.
The picture is also a little blue- cool looking, so it could be 'warmed' up a bit by increasing the colour temperature.
You'll also need a model release.
There is a problem with the baby's eyes. It gives the impression of double pupil. On the left side of the baby's neck is color fringing - the wall, window, and neck. The baby's hair shows excessive color noise. Zoom to 100% and you'll see it all.