We know that Peter was married because Christ healed his mother-in-law. Do we know if he had children? Do we know whether any of the other apostles were married and if they had children?
Eusebius of Caesarea's Church History talks a bit about this.
He says St. Philip, at least, had 4 daughters and Sts. Peter and Paul had wives.
Regarding St. Paul (although not one of the 12):
There's nothing that I know of in the Scriptures that indicate whether or not they did, aside from the mention of Peter's mother-in-law. So, it seems we can't know for sure.
However, the norm was that men would have wives and children. When things conform to the norm, it isn't necessary to mention that. It is only notable if something goes against the norm. So, one reason to conclude that the apostles did have families was that this would have been the norm, and we have not mention of them being different from this norm.
I do understand that this is an argument from silence, but either side would need to be that way.
Another consideration is that if the marital status of the apostles had been in any way significant or important for us to know, then there would have been ample mention of it. We do know that Peter had a wife. The normal occurrange would be that they were all married and that they all had children.