J.
Are you kidding me. Our third daughter had a terminal birth defect. She died 7 minutes after being born. When we were blessed to have another we didn't care what it was as long as it was healthy. The HR ultra sound showed that our 4th may have a club foot. It didn't matter he didn't have the birth defect that his sister had. We saw he had a skull and we were happy past that it didn't matter.
He was born premature and was in the nicu for 10 days. He is perfectly healthy now Thanks God, but it wouldn't matter. Your children are not yours they are Gods, he allows you to assist him in caring for his children. Consider yourself blessed that you can have 2 healthy babies and be done with it. If your MIL does't get that you don't need her in your childs life.
J.