Which basic fertility tests should both of us do before starting any treatment?

Typical first-line workup: For the woman: a pelvic ultrasound with antral follicle count, AMH (ovarian reserve), thyroid (TSH), prolactin, sometimes day-2/3 FSH/LH/estradiol, and a check that the tubes are open (HSG or a sonosalpingography/saline-contrast scan). For the man: a semen analysis after 2–5 days of abstinence. If it's abnormal, it should be repeated after a few weeks since results vary naturally. Both: relevant infection screening as advised. No special preparation is needed for most blood tests, but tell the lab/doctor about any medicines. Bring any earlier reports with you — they save repeat testing.