Hi, and thanks for your medical question on eHealth forum!
If you and your partner have been trying for kids for 6 years and you have not had kids earlier, then you should consult an infertility specialist. There are various reasons for this like ovum not being formed, polycystic ovary, hormone imbalance, hypothyroidism, local infection, blocked tubes etc. In males it can be infection, STD, varicose veins, hydroceles, poor sperm count, not enough motile sperms etc.
You will need tests like Hsg or hysterosalpingography, laproscopy , hormonal level and pelvic sonography, glucose challenge test, thyroid profile, ultrasound guided graffian follicle maturation (in this the growth of ovum is monitored by ultrasound and then specific drugs as needed are given for ovulation and maturation of ovum) and antisperm antibody test. PAP smear, STD panel are the other tests done. Semen analysis is performed.
Since a confirmed diagnosis cannot be given on net and without running some basic tests please discuss these possibilities with your gynecologist once. Hope this helps. Take care!