There may be some other elegant ways, but you could use the If...then... rule combines with special symbols that replicate checked/unchecked box

Daniel

Use an If...Then...Else field that checks the entry in the Gender field and
inserts a checked box in the Male checkbox if the gender is male and an
unchecked box in the Female checkbox  and vice-versa if the gender is female

To do this, at the location where you want the male check box to appear,
press Ctrl+F9 to insert a pair of field delimiters {} and inside them type

{ IF }

Then with the cursor before the closing }, press Ctrl + F9 again to insert
another pair of field codes and type in

( IF { MERGEFIELD Gender} = "male" "" "" }

Now, place the cursor between the first set of "" after "male" and from the
Insert Symbols dialog, insert a checked box Character Code 254 under the
Wingdings font.  In between the second set of "", insert the unchecked box
symbol -  Character Code 168 under the Wingdings font.

In the location where you want the female check box to appear, insert the
same field construction, including the symbols but change the "male" to
"female"  (copy and paste is the easy way)

( IF { MERGEFIELD Gender} = "female" "" "" }