is it bad?

Question
My question is, is it bad to have a female golden retriever puppy, and a male golden retriever together in the back yard when the female is in "heat"? Its her first time, and my family is worried that he might do something to her(try to get her pregnant). The male dog is just 1 year old, and he hasn't been humping anything.

     Should I separate them?

Answer
Please don't do it.  You can almost count on her bearing a litter she isn't ready for.  In some cases, accidental breedings produce not puppies, but infections.  Even neutered males sometimes mate with a female in heat and casuse infections.  So how secure is your yard?  Do you have a 6 foot fence?  I have seen reports of accidental breedings where somebody thought a 6 foot fence was safe and a dog jumped it.  

It sounds to me like you plan to be breeding them later despite not knowing the basics.  Those doing so create no end of problems, including the millions of dogs we slaughter for lack of homes every year.  For a look at what responsible breeding involves, read through http://www.woodhavenlabs.com/articles.html#breeding