[chrimill]

I just ran a poker stove where i gave UTG+1 ATC and BB all the reasonable hands that would connect moderate to good with this flop,(i.e. A7, pocket pairs 33-99 and all the low connectors that would now have two pair, pair+gut) and we have a 51.2% equity. This assumes he would slowplay a straight, adding a flopped straight into the mix changes our equity to 42.3%, still good enough to raise if UTG+1 literally has ATC(which is probably not the case). So I believe that the answer as to whether you should raise the flop depends on what you think the BB's range is, if it includes all hands that connected well with the flop wait until the turn and re-evalutate based on the action. If it is skewed more towards hands that connected moderately, i.e he is betting all one pairs, two pairs, and draws and slow playing monsters(sets and straights) then a raise is definitely in order. Put another way, since you can't eliminate UTG+1 with a raise and you can't reasonably put him on a hand use the BB's betting range as a guide for your actions.