Comparing network properties of 2 groups of unequal sizes


This may be a basic question.

I wish to compare networks of 2 groups:
1st group: Controls. Size 30.
2nd group: Patients. Size: 80.

How should I best control for age and gender, for instance, before doing any further analyses?

Can I take only 30 patients whose means, variances match closely to the mean, var of the group, so that they represent the group well?

Many thanks!