In Re the Marriage of Detert

*708DONIELSON, Presiding Judge.

Respondent, Ned Detert, appeals from the district court’s denial of his application to modify the decree annulling the parties’ marriage. The husband contends the district court erred: (1) in concluding he was barred by the doctrine of res judicata from introducing evidence of nonpaternity in support of his application for modification of the annulment decree; (2) in concluding the paternity exclusion established by a blood test not available at the time of the annulment did not constitute a substantial change in circumstances pursuant to Iowa Code section…