In reply to Adele.

You are asking about how to slice the regression surface when there are multiple explanatory variables. For your example, if MIN is the minimum weight and MAX is the maximum weight, you can visualize the model by creating the following scoring values:

data Score;
MIN = 2500; /* grams */
MAX = 5400; /* grams */
do sex = 'F', 'M';
do bWeight = MIN to MAX by (MAX-MIN)/50;
output;
end;
end;
drop MIN MAX;
run;
proc print;run;