Hello
Welcome here.
I can understand your concerns.
First, i would like to tell you that
masturbation is a normal process and does not affect sexual capacity.
Second, DNA test does not decide the fertility capacity.
For you, go for
semen analysis to the status of your sperm count, motility, morphology etc.
For your wife, go for the following tests:
Hystersalpingogram to know status of uterus and tubes;
Hormonal assays (LH, FSH,
Progesterone and androgens)
Ultrasound,
Ovulations assay.
Menstrual irregularities can also be a contributory factor.
These tests will determine the cause of
infertility and guide in treatment.
Consult your nearest infertility specialist.
Hope this helps.
Thanks.