Endocrinologist says one thing and Ob/Gyn says another...?

I am confused. My ob/gyn said according to my blood tests, my thyroid is fine and has no issues. She said it would in no way affect my fertility. However, my primary doctor said I have mild hypothyroidism with a multinodular goiter (you can feel it even) and sent me off to an endocrinologist who sent me for several tests of my thryoid (biopsy, nuclear scan and ultrasound) and confirmed that I have Hashimoto's disease. Why is my ob/gyn still insisting there is no problem? This is the second one to say my thyroid is fine - clearly it's not. Do they know anything about your thyroid? Why would she keep insisting there is no problem when clearly there is - confirmed by 2 separate doctors? THIS is contributing to my infertility but my ob/gyn says that's not true.. WHAT? Can someone tell me why there is such a discrepancy?