A church without children is not a church that is going to survive. A lack of families is also a warning sign that something may be very wrong. Church should be a place where Christian parents take their children to help them being their faith journey. If the parents are unwilling to expose their children to a church for some reason, there should be warning alarms going off in every part of your head. There is not necessarily something sinister afoot, but if the sermons are so heavy on the fire and brimstone that kids are having nightmares or filled with such esoteric theology that the Sunday school class is baffled, it is probably time to move on to a new church. 

Being a church for singles is not an acceptable excuse. Assuming the church is really focused on God, there would likely be at least some families in the congregation. If the church is so heavily geared toward single people that couples and families do not feel welcome, there are bigger problems afoot in the church culture, and they are not ones in which you want to be embroiled.