rather than the decline in fertility being because of illness.

[GoodTaste]

“We always knew that these post-reproductive females were around,” says co-author Kevin Langergraber, a primatologist at Arizona State University in Tempe, who has been studying the Ngogo population since 2001. But he says that it was a surprise to realize that the chimpanzees were undergoing the same physiological process as humans, rather than the decline in fertility being because of illness.

Source: Nature Menopausal chimpanzees deepen the mystery of why women stop reproducing

I don't understand why the word "being" is inserted here. It seems to be redundant and can be removed altogether without affecting the meaning.
I am not absolutely sure. Does it have any function?

 

[Tarheel]

The word "being" is not inserted there. Maybe you mean "used". In any case, it should be the other way around. That is, you should explain how you can use the sentence without that word. (It's essential.)

 

[GoodTaste]

rather than the decline in fertility due to illness
rather than the decline in fertility because of illness
Both the above work well without being.

Essential? What reasons do you hold to support your case? Please make some sentences to show your mind.

 

[Tarheel]

I'm not the one who has read something by professional writers and decided that they don't know what they're doing.

My opinion has not changed.

 

[Piscean]

rather than the decline in fertility due to illness
rather than the decline in fertility because of illness
Both the above work well without being.

They don't. They suggest that illness was the cause of the decline in fertility. the original tells us that something else was the cause.

 

[GoodTaste]

That is just a news article intending to promote popular science.
It is for lay audience and not necessary professional.

 

[GoodTaste]

They don't. They Suggest that illness was the cause of the decline in fertility. the original tells us that something else was the cause.

If something else was the cause, why role does "illness" play in the process of the decline? That is, what does "being" mean? Can you use another word or phrase to rewrite the sentence with the same meaning?

 

[SoothingDave]

Illness plays no role! That's the point. Instead of illness causing the decline, it is caused by a physiological process.

 

[jutfrank]

The verb being is crucial to the logical structure of the sentence so it can't be removed. Look at the following proposition:

The decline of fertility is because of illness.

The copula is is needed to connect subject with predicate. The verb being occupies the position of copula in the non-finite clause used in the original sentence.