First off, don't listen to your doc about that study. It maybe right slightly over half the time. Maybe. Both my boys were in the 160s-170s. I had heard that, too, and was wanting a girl. It gave me false hope.
Second of all, I can totally understand why you would feel this way. Maybe you could talk to your husband and tell him how you feel. Let him know that his feelings about his daughter's gender are worrying you and you don't want to disappoint him. Although technically you have very little to do with the gender determination, if anything. Nothing has ever been PROVEN. And take comfort in the fact that he loves his daughter now. He will likely have a period where he is disappointed and will possibly even act a bit childish about it. Just try to realize this has nothing to do with you. YOU are not disappointing him. The gender of your baby is largely out of your control. The hardest thing for you will be to NOT take your husband's disappointment on yourself. Relax and realize he will feel that way regardless of anything you do. Come alongside him and try to understand him and be sensitive to his hurts, but don't allow him to bring you down with him. If his attitude begins to do that, take a break and go somewhere for coffee or something. Do you have any close friends you can talk to about this? I am not advising you to talk behind your husband's back, but sometimes having one good friend to go to for advice in a specific situation or event can be worth so much! Also talking to him about the possibility of having another girl may help. Maybe try pointing out after a particularly special moment he shares with his daughter that it really wouldn't be so bad to have another one of those. Not too much, or it will get on his nerves. But just gently here and there.
That's my best advice. I wish you luck and less stress. RElax and take the load off! IT isn't your fault or responsibility just like it isn't my husband's fault for giving me 2 boys!