Male Feminist League is a tongue-in-cheek paraphrase and an antidote to the expression 
'male chauvinist pig' , which, hopefully, is the thing of the past, but  may still need some  commentary.

 

XX vs XY

 

XY it's as if one of 2nd X's little legs was broken off and replaced by penis. 

At first, we all start off as female embryos.  Some, I believe, being somewhat less then perfect, are sorted out to be males in the future. After all, females are much more universal - they can create babies (though not without male help so far).

 

Here is an illustration to this thought: there is a genetic defect called 'Testicular Feminization'. A girl is born and raised. It is discovered that by the age of 13 -15 years, she has failed to menstruate and is taken to the doctor.  The doctor examines the 'girl' and states that this is, in fact, a boy, whose tissues are not sensitive to the male hormone. He does not have a uterus with ovaries, nor a vagina, but has testicles stuck in the 'labia majora'. 

 

All the elements of the penis are built in, as usual, in the female configuration of genitalia.