This really is a success story ! Vasectomy usually involves cutting the tubes carrying sperm from the testes ("balls") to the penis. Reversal re-joins those tubes ....but it's not that simple. The success rate (with pregnancy resulting) is indeed 50% or less. It depends on time after vasectomy (best within 10 years),the female partner's age (under 35) , and (as with any operation) the surgeon's experience. Mr Duncan Harriss performs over 10 reversals / week. What he charges (over £2,500) is the going rate for such operations. They are not likely to be available on the NHS, and where they are, there is a long waiting list.
The remarkable biological fact in all this is that despite vasectomy, sperm continue to be produced, and that's why reversal may be successful, as in Gwapito's case ! Congratulations.