No..it is not wrong to want a baby
Pray together and seek God's face together as you are one...in all things seek the Lord together as you will find wisdom and strength...
I agree with MaryJane but wanted to add that with God nothing is impossible. God can can heal you of your rare disease. Should He chooses not to, you can still have however long sharing your love with a blessed child from God.
Besides, we never know how many days we have here. I could die today, but would have spent 8 happy years with my precious daughter. God Bless you both. I will pray for Gods perfect wisdom and knowledge regarding is situation.
Love in Christ, Eva