Stephen Stills – "Change Partners" (1971)

So we change partners

Time to change partners

According to Greek mythology, Castor and Pollux were fraternal twin brothers who had different fathers.  

Castor was the mortal son of King Tyndareus and Queen Leda of Sparta.  But Pollux was one of the immortals, because his father was Zeus – who had taken the form of a swan and seduced Leda after she had sex with her husband.  (In some versions of the myth, that Zeus-Leda coupling also resulted in the birth of Helen of Troy.)

"Leda and the Swan" (Rubens)

Castor and Pollux got into a fight with two of their cousins over the ownership of a herd of cattle, and one of the cousins killed Castor with a spear.  As the son of Zeus, Pollux didn’t have to worry about dying, but he was devastated by his brother’s death.  

Zeus transformed the brothers into the two brightest stars in the constellation Gemini so they could be together forever.

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The myth of Castor and Pollux illustrates the phenomenon of heteropaternal superfecundation – The term used to describe the fertilization of two or more eggs produced during the same cycle by sperm deposited by different fathers.  (Homopaternal superfecundation is the term used to describe the fertilization of two or more eggs produced during the same cycle by sperm deposited during two separate acts of sexual intercourse by the same father . . . which is much less naughty.)

Statues of Castor and Pollux in Rome

Genetically, Castor and Pollux are only half-brothers.  By contrast, the offspring of identical twins who marry identical twins are genetically as similar as siblings – but we consider them to be cousins.

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Heteropaternal superfecundation is more common in animals such as cats and dogs than in humans for two reasons.  

First, female cats and dogs routinely produce several eggs each time they ovulate (unlike human females).

Second, female cats and dogs are somewhat more receptive to having sex with multiple partners in a relatively short time span.  (Human females – most of them, at least – are more discriminating.)

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In 2015, a mother of twins went to court in New Jersey to force the man she said was the father of those twins to pay child support.  When she admitted that she had had sex with another man at about the time that she became pregnant, the judge ordered a paternity test.

It turned out that her twins had two different fathers.  So the man she had sued was ordered to pay child support for one twin but not the other one.

In the words of the New York Times, “It was a tangled web of love and biology.”  

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I’m guessing that a lot of instances of heteropaternal superfecundation go unnoticed.

After all, siblings don’t necessarily look that much like one another, and fraternal twins are just siblings who happen to be born at the same time.

The problem comes when there is a difference in the appearance of the twins that makes it obvious that the father of one isn’t the father of both.

Oops!

For example, imagine you have a white mother and a white father, and one of the twins looks a lot like Barack Obama looked like when he was a baby.   

Lucy . . . you got some ‘splaining to do!

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Stephen Stills’ “Change Partners” was released in 1971 on the Stephen Stills 2 album.

Its lyrics were apparently inspired by the country-club dances that Stills attended as a young man growing up in the South – dances where young women often danced with as many different partners as there were musical numbers performed during the course of the evening.

But some viewed the song as a metaphor for the constant comings and goings of the individual musicians who had at one constituted Crosby, Stills, Nash & Young.

The recording features Jerry Garcia on pedal steel guitar.  

Here’s “Change Partners”:

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