Hello, thankyou for approaching DoctorSpring.com with your query.
Yes, by being on replacement therapy with Testosterone, although your testosterone levels would be maintained but pituitary hormones LH, and FSH will get suppressed causing suppression of sperm production, thus affecting your ability to produce a child.
The reason for low testosterone in your case is not clear. If it is due to pituitary hormone deficiency, then hCG (LH) and FSH may help.
If the cause is at the level of Testes (your LH , FSH levels will be high then), then hCG will not help.
Please can you upload your test results so that I can give you an informed opinion.
Reply as a follow up.