What makes a person homosexual is a mystery still to be revealed
— as well as a sociopolitical hot potato. But let’s talk about
what the oxytocin hypothesis might mean for same-sex relationships.
Certainly, gay men and lesbian women love and bond the same way that
straight people do. Their hypothalami produce the same spurts of
oxytocin and vasopressin, and they enjoy the same exciting rushes of
dopamine. Sex creates the same association in the brain’s reward system
between a sex partner and feeling great, inscribing a social memory
that causes one person to prefer another.
In gay love, however, limbic resonance — that condition in
which two people’s physiological states become attuned — may be,
well, more resonant, because the lovers’ systems are more alike than
those of a heterosexual pair.
There’s an old joke in the gay community: What does a lesbian bring
on the second date? A U-Haul. What does a gay man bring? A friend.
There’s some neurochemical truth to this joke. When two women have sex,
the oxytocin surge can induce cuddling that lasts for days. Two male
lovers, under the heavier influence of vasopressin, to say nothing of
testosterone, may quickly feel ready to move on physically and
emotionally after lovemaking.
In addition to the match in brain chemistry in same-sex couples,
there’s evidence that one partner — gay or straight — can
absorb the other’s sex and bonding chemicals; in a same-sex couple,
this could heap on an extra helping of estrogen or testosterone.
Estrogen and testosterone may be exchanged via lovers’ sweat and
saliva. How do one person’s sex steroids get into the other person’s
brain? Most mammals have a special area in the nose called the
vomeronasal organ. This sensitive tissue, located in the nasal
passages, sends molecules inhaled by the animal directly to the brain,
where they can influence behavior. This organ reacts to pheromones, the
chemical-signaling substances put out by many animals, from insects to
apes. It’s the organ that draws a female elephant to the temporin
secreted by a bull in his prime.
Human fetuses have a vomeronasal organ, and for a long time,
biologists thought that it was a vestigial structure that disappeared
by birth. But recently, researchers have found evidence that the human
response to pheromones is alive and well in adults.
If people of all sexual flavors react to the neurochemicals they
swap when they canoodle, in a gay couple, this may reinforce their
neurochemical states. Remember, estrogen increases the effects of
oxytocin, while testosterone decreases them. So, with every nuzzle,
taste, and touch, a same-sex pair creates a neurochemical feedback loop
that reinforces the tendencies of their sex.
When two women engage in intimate behavior, from hanging out with a
friend to wild lovemaking, it’s likely that, with every breath, each
takes in molecules of estrogen and oxytocin emitted by the other’s
body. Two men enjoying the same behaviors likely inhale each other’s
testosterone, oxytocin, and vasopressin. Overall, two women may
experience more oxytocin in their relationship than a man and a woman,
and two men may experience less oxytocin and more vasopressin.
It’s crucial to note here that all men and women — gay,
straight, and in between — possess a wide range of temperaments
and tendencies. Men gay and straight may find it extremely easy to
bond, while women of all sexual persuasions run the gamut from
runaround to stay-at-home. The important thing is that for all of us,
gay and straight, the neurochemistry of bonding is the same.
