SELECT fname ,  sex FROM Student WHERE StuID IN (SELECT StuID FROM Has_allergy WHERE Allergy  =  "Milk" EXCEPT SELECT StuID FROM Has_allergy WHERE Allergy  =  "Cat")
What are the first name and gender of the students who have allergy to milk but can put up with cats?
[Schema (values) (types)]: | allergy_1 |  Allergy_Type : allergy (text) , allergytype (text) | Has_Allergy : stuid (text) , allergy (text) | Student : stuid (text) , lname (text) , fname (text) , age (number) , sex (text) , major (number) , advisor (text) , city_code (text);