Can anyone tell me is ventricular septal defect a genetic defect?

Rarely: At our current level of understanding, we do not find identifiable genetic abnormalities in the great majority of children with an isolated vsd. Having said that, there are genetic diseases, such as down syndrome, or digeorge syndrome that have an increased likelihood of vsd. This is an area of active investigation and it is likely that our understanding will advance over the next few years.

Not directly: This defect is not like eye color. You don't have a VSD gene hanging around that causes the defect. There is evidence that genes influence the defects (CHD's). If you have a CHD you have 4% risk of your kid having one of many CHD's. If both parents have a CHD,the risk would be about 8% of a child of the pair with a CHD. This is a complex issue.Consult a medical geneticist if needed