Hello
As you mentioned that your wife is taking anti tubercular treatment ( productive -F and reninizide tablets , that's a nice thing).
First of all upload detail reports of
SEMEN analysis . As you mentioned that there is 20 million SPERM count ( you didn't mention
total sperm count or / mL i.e. normal sperm count is 60-120 million total , while 30-40 million / mL).
So first of all I want to tell you is that your SPERM count is less than normal for
fertility . Also get in morphology and motility of sperms and upload these reports also .
Fertility and subfertility is associated with motility and morphology of sperms .
After this get in an
ultrasound of both ovaries of your wife . Also get in study of dominant follicle size as this decides whether there is successful OVULATION or not .
If follicle attain full size ( 19-20 mm at the time of rupture ) and burst and liberate ovum , there will be conception.
So first of all get in SEMEN analysis ,then ultrasound of both ovaries of your wife , then follicle study , then ovulation study.
So consult a fertility specialist and get his opinion.