Immaculate conception is back in the news. No, not the sort that underpins the story of Mary, mother of Jesus, born to infertile parents who did not have sexual intercourse.

We're talking about Charlotte, a stingray in an American aquarium, which conceived four pups despite not sharing her tank with a male ray for eight years.

Charlotte had the company of small sharks, and at first scientists wondered if somehow they'd mated with the stingray. But this theory didn't hold water - there was no shark-stingray hybrid. Instead, they think the stingray reproduced herself through a process called parthenogenesis, from the Greek words "parthenos" for virgin and "genesis" for creation.

Parthenogenesis is when an egg creates an embryo without sperm - a virgin birth, if you like. Some insects are capable of it but parthenogenesis is rare in vertebrates like Charlotte.

But there is one species of lizard - the whiptail, found in Mexico and California - which has dispensed with the need for males entirely, instead relying on parthenogenesis to reproduce.

Imagine that. A society free of the tensions gender differences impose on the rest of us. No mansplaining. No misogyny. No unwanted sexual advances. No quarrels over whose turn it is to load the dishwasher. You want kids, you produce them yourself. Could this be the future for the human race?

Before you scoff, consider this: in 2017, scientist Dr Shanna Swann and her research team published a landmark report showing that over the preceding 40 years the sperm count in males in Western countries had declined by about 50 per cent. Alongside that decline has been a sharp increase in the number of people resorting to IVF to have children.

And even more recently, the conversation has turned from the population explosion to its decline as fertility rates across the world shrink.

South Korea is at the pointy end of the fertility crisis. To maintain a steady population, it needs a fertility rate of 2.1 children per woman. Instead, its fertility rate has dropped to a record low of 0.72 children per woman.

In China, the population has decreased for the second year in a row. After dumping its one-child policy in 2016, it now has a three-child policy, offering tax incentives to parents to have more babies. But the Chinese version of Peter Costello's "one for Mum, one for Dad and one for the country" is falling on deaf ears.

There's likely more than one reason for declining sperm counts and fertility rates. Part of it might be social. More women engaged in the workforce means less time for children. Priorities once focused on family have shifted towards career.

But Shanna Swan is concerned about the environmental factors affecting the reproductive landscape, specifically the growing array of hormone-disrupting chemicals to which we are exposed to in our daily lives.

"These endocrine-disrupting chemicals are playing havoc with the building blocks of sexual and reproductive development," she wrote in her 2020 book Countdown.

"They're everywhere in our modern world - and they're inside our bodies, which is problematic."

Back to Charlotte's immaculate conception. Are we facing a dystopian future in which our species will only survive through a process like parthenogenesis or, worse, by being manufactured in test-tubes, like the people who inhabit the pages of Aldous Huxley's terrifying Brave New World?

HAVE YOUR SAY: Is the decline in human fertility and sperm counts concerning? Have you or members of your family had to use IVF to have children and how was the experience? Email us: echidna@theechidna.com.au

SHARE THE LOVE: If you enjoy The Echidna, forward it to a friend so they can sign up, too.

IN CASE YOU MISSED IT:

- Cars and small trucks in Australia emit more carbon dioxide than the coal produced in some of the biggest mines in the country, according to the Climate Council. The environmental pressure group identifies what it calls the "filthy five" car makers "whose fleets are responsible for more climate pollution than some of Australia's biggest coal mines".

- Former fighter pilot Daniel Duggan is fighting to push back a court date that will decide whether he is eligible for extradition to the US as his legal bill nears $1 million. The ex-top gun's lawyer, Jolan Draaisma, appealed yesterday to delay extradition proceedings on the grounds Duggan and his supporters were still seeking funding to pay for his legal defence.

- Half a dozen properties in three states have been raided as part of a probe into how the deadly varroa mite reached Australia, the bee industry says. The Australian Honeybee Industry Council says federal police have targeted properties in southern Queensland, northern NSW and Tasmania in recent months.

THEY SAID IT: "The difficulty of IVF or of any fertility issues is the hope and the shattered hope, the dream that it might happen this time and then it doesn't happen." - Brooke Shields

YOU SAID IT: Young people might be the ones who save the greeting card tradition.

"I am about to move house and in the process have unearthed chosen letters and cards that I am so glad I retained," Sharon writes. "Your comment resonated particularly when I found a card from my aunt who died a few years ago. We had a close but difficult relationship at times and she was incredibly supportive when I found myself parentless at 18. As I read her words they became her voice in my mind and I felt her presence more strongly than I had for a long time. It evoked feelings that could not have come from any other medium and despite a tendency to dwell on the moments we clashed, this left me with a feeling of positivity and love. I urge everyone to put pen to paper, and to indulge in a little hoarding of those treasures."

Annette writes: "I still send friends and family cards or written notes. And I love getting them, although the majority of friends/acquaintances defer to the electronic version. When recently cleaning up some old cupboards and boxes, I came across invaluable birthday cards, Christmas cards, 21st birthday keys (from another century) and letters, and immersed myself in a wonderful memory tour. I felt the writers/senders sat with me while I revisited them, reading our history together . No electronic version comes even close. I hope things change, modern communications having their place, but not at the cost of the more personal and meaningful contacts."

"My sister (mid 70s) still has a letter written to her from our grandmother in 1962," Gail writes. "Our Nan was the only family member who had contact with us in a children's home. We sat together recently and read and re-read her letter telling us to be good girls - it wasn't the words that were written but seeing her writing fading away on this small sheet of paper - our only connection to our childhood. The Echidna is my first read every morning and as always, positive and inspiring. Thank you."

Stafford writes: "In 1961, I moved into a new home at Cabramatta. I worked as a session musician and needed a phone. The Post Master General told me I had a two-year wait, a death sentence to my career, so I wrote to my local member. A couple of weeks later, a reply arrived in flowing longhand: 'Fear not comrade, help is at hand. Gough.' A week later, the phone arrived. Help was indeed at hand. Unfortunately, I did not keep the letter."

"It is extremely difficult to throw away cards," Sally writes. "We had a recent cull, both my husband and I going through cards from the last nine years. Job done but there are still two other boxes that were sorted through before. I have left messages in some, and I wonder how our family will feel if they decide to go through them when we finally pass this mortal coil."

Elaine writes: "You have struck a real chord in this reader's mind. Like you, I can't throw out cards and letters from family and friends. Recently I have had reason to 'go through' boxes and boxes where I have stored these treasures. I found a cache of letters from the 1980s from a dear friend who passed away recently. It was a real 'tear jerker' to read them again in his handwriting. Fortunately I found them before his funeral so I was able to mention some episodes in a letter of condolence I gave his sons at the funeral, each with their own card. For a retired teacher, some of my most treasured letters and cards are from former students. Re-reading them brings comfort and joy."

"The sentimental memories of handwritten notes and cards or gestures of kindness keep that feeling of connection alive in our hearts and memories," Tanya writes. "My grandmother passed away over 30 years ago. I found a handwritten note under her sewing machine. It was written in wobbly pencil on a small piece of scrap paper by the then-six-year-old me, thanking her for the new jumper she had knitted and the new coat she had lovingly made for me all those years ago. I still keep that fragile note tucked away with my sentimental items."

Joan writes: "Yes handwritten carries more thought and is more appreciated than digital communiques. I have often visualised the responders of those birthday reminders on Facebook as they rush to their workplace or are swallowing a cuppa, 'Gosh! Joan's birthday today. Tap tap tap tap tap. Smiley emoji. Candles, clinking glasses and bottle of bubbly. Right, that's done!' Then there's the card. She's called into the newsagent, spent a half hour laughing at the funny cards and found one 'just right' for Joan. Added her love and best wishes and addressed and stamped it to put in the mail. Love it. Even more important to be human when sending sympathy. I've had birthday wishes on Facebook from people I knew years ago and haven't seen (or wish to see) forever."