Did Christ's original twelve apostles have families? 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. 


  Clement, indeed, whose words we have just quoted, after the above-mentioned facts gives a statement, on account of those who rejected marriage, of the apostles that had wives. "Or will they," says he, "reject even the apostles? For Peter and Philip begot children; and Philip also gave his daughters in marriage. And Paul does not hesitate, in one of his epistles, to greet his wife, whom he did not take about with him, that he might not be inconvenienced in his ministry."


Church History Book III

Regarding St. Paul (although not one of the 12):


  Paul was obviously unmarried when he wrote this verse. Some interpreters believe that he had previously been married and widowed; there is no clear evidence either for or against this view, which was expressed already at the end of the second century by Clement of Alexandria.


NABRE - Commentary on 1 Cor 7:8