Children don't need Xrays or blood samples. The medical for kids is really simple and for a baby it should be a formality. For my daughter (aged 5) the nurse measured and weighed her, did a very basic eye test (telling what the pictures on a chart were), tested her urine. The doctor then checked her with a stethascope, checked her glands in her next, stomach, spine and ankles. That was about it. Still cost $300+ though!
Don't sweat the medicals - they're not so strict unless you have a long medical history or they find something seriously wrong. I passed and I'm in terrible shape...