There's no evidence that children of athiests are not brought up to be good moral citizens. Children who dont behave in a socially acceptable way, generally, though not always, are a result of bad parenting.
Well i personally think the lack of elder respect, lack of sexual moral, lack of gratitude, extreme selfishness, extreme materialism, general lack of respect, etc etc so on and so forth that has gradually become worse and worse lets say since....1960, to tie in the the massive decline in religious following is more then coincidence. I was watching a programme called worlds stricted parents on bbc three, where British tearaway teens are sent to foreign lands to see what real life is really like for some people, they went to a bible bashing house in olklahoma where the parent-child relationship with firm but loving each way, they went to a hindu mans house in india, same there, catholic family in i think nigeria or somewhere, and i quote the nigerian mother " The moral fabric of the United Kingdom is weakening"
Nobody has said religion is the be all and end all, but its much more likely to set a child on a righteous moral path in life then those without, even italian gangsters have more respect for their nonnas then the average UK teenager.
As for citing lack of evidence, evidence is factual proof, and on subjects like these, factual proof isnt applicable, because it cant be, we're debating a relatively unprovable theory.