Time limit to enter USA after visitor visa was issued

[ssparimi]

My Parents were issued with 10 year visitor visa. They are yet to come to US. Couple of my friends are mentioning that first time my parents should enter US within 6 months from the date the visa was issued.Is there any stipulation like that? Can some one tell??

Thanks in Advance
Manyam

[peace]

This q is covered under FAQs.

No there is no 6 mnth rule. It is a myth. Travel anytime during the validity
period.