An initiative of the United States Conference of Catholic Bishops

FAQ Series: What is Sexual Difference?


For the next 5 weeks, MUR will be going over a few of the FAQs on our website. This week we cover #5: What is sexual difference?

This is one of those funny topics: it seems that you have to be educated to overthink this one. Children basically understand it without too much explanation.

Simply speaking, sexual difference is the difference between men and women, boys and girls.  On one hand, it is the most obvious fact of human existence that we all are either one or the other*.  The announcement of a doctor, nurse or midwife attending a birth is, “It’s a boy!” or “It’s a girl!”

Every cell in the human body has chromosomes that are either XX or XY, and that seemingly small fact determines many things.* It determines how the baby develops in utero, and affects what hormones are prevalent in their bodies throughout their lives. Sexual difference affects a person at every level: genetically, biologically, emotionally, psychologically, and socially.

Sexual difference can accurately be called an “irreducible” difference; this means that there is a fundamental difference between man and woman that cannot be overcome, ignored, or glossed over except to the detriment of the person.  We cannot pretend that the difference does not exist, or that it does not matter.  Sad things happen when this is attempted.  Instead, we can celebrate our differences and be curious about the gifts that the other half of humanity offers us.

It is a good thing that we are not all the same. Today it may sometimes be hard to acknowledge sexual difference because we fear falling into the abuses or traps of the past, where women were not valued or treated as equal in dignity or responsibility to men. Sexual difference does not and should not mean “opposition or subordination.”  As Pope Francis said, “For example, I ask myself, if the so-called gender theory is not, at the same time, an expression of frustration and resignation, which seeks to cancel out sexual difference because it no longer knows how to confront it. Yes, we risk taking a step backwards. The removal of difference in fact creates a problem, not a solution.”

It is only because of sexual difference that two human persons can unite in a total and complete way in marriage. In the words of Carson from Downton Abbey, marriage is when “two persons become as close as two persons can possibly be.”  This is what the difference is for: not to divide, but to make spousal union possible.  Puzzle pieces cannot be joined together if they are the same! And while human beings can do lots of things on their own, procreation can only be accomplished by the two sexes together.

The video “Made for Each Other” is all about sexual difference. “Made for Life” also addresses it, particularly from 7:20 – 8:50.

*The phenomenon of hermaphroditism or an “intersex” condition will not be discussed in this blogpost. Today we are focusing on the normative development of the human person. “Intersex” diagnoses are estimated to be 0.018% of the population. (Leonard Sax, “How common is intersex? a response to Anne Fausto-Sterling.” Journal of Sex Research, 2002 Aug; 39(3):174-8.)  The rest of the blog post is assuming the norm.

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