when using the if macro you have to make sure to also have the closing to it:
<<if $variable is "this">>
statement.
<</if>>
if you're going for something a bit more complicated, like a scale, it may look a bit more like:
<<if $masculine <= 5>>
statement.
<<elseif $masculine <= 6>>
statement.
<<else>>
statement.
<</if>>
I could link you some sugarcube tutorials if you'd like.