Steve Connor: Why sexual equality is nature's ideal

Science Notebook

Share
Related Topics

People often ask me if there is a biological reason for there being a roughly 50:50 ratio of males to females in the population. If one man can inseminate hundreds of women in his lifetime, surely there is no biological need for so many males to be born.

The question came up again the other day with a study showing that there was a very slight, but statistically significant, increase in the probability of a woman giving birth to a baby girl the nearer the mother lives to the equator, compared to mothers who live in more northerly or southerly latitudes.

The slight bias towards girls as you move to the equator may be a remnant trait of the seasonal nature of human reproduction when we lived a hunter-gatherer existence. In any case, the 50:50 ratio is still biased overall to males, with about 106 boys in the world being born for every 100 girls, because males are more likely to die in childhood.

But that still leaves the 50:50 question. The answer was in fact solved in the 1930s by the mathematical geneticist Ronald Aylmer Fisher. In essence, it's because in a population heavily weighted to females, it becomes an advantage for a mother to give birth to males, and vice versa if the population gets skewed towards males. In effect there is a perpetual balancing act in evolution that keeps the human sex ratio at about 50:50.

Milking a whale of a tale

A story popped up last week on the Planet Earth website of the Natural Environment Research Council about a nutritious alternative to cow's milk. Scientists at its Marine Research Institute in "Mid Glamorgan" devised a way to milk Minke whales, producing 40 times more milk than cows. They trained pods of the whales to be milked in a Norwegian fjord. It sounds implausible... because it is. Now 1 April is behind us, we can give a little sigh of relief for another year.

Riot of a man

While we are on the subject of April Fools' day, the anti-capitalist demonstration in London threw up an old face in the shape of Professor Chris Knight who has been suspended from his post at the University of East London for inciting people to eat bankers. I remember Chris from years ago when he came up with the "sex strike" theory for human menstruation. It's too complicated to be explained here but it involved stone age man (and woman), a full moon, red ochre, hunting meat and making whoopee.

React Now

iJobs Job Widget
iJobs General

Information Security Manager (ISO 27001, Accreditation, ITIL)

£70000 per annum: Harrington Starr: Information Security Manager (ISO 27001, A...

C# Developer (HTML5, JavaScript, ASP.NET, Mathematics, Entity)

£30000 - £45000 per annum + Benefits + Bonus: Harrington Starr: C# Developer (...

C# Integration Developer (.NET, Tibco EMS, SQL 2008/2012, XML)

£60000 - £80000 per annum + Benefits + Bonus: Harrington Starr: C# Integration...

Biztalk - outstanding opportunity

£75000 - £85000 per annum + ex bens: Deerfoot IT Resources Limited: Biztalk Te...

Day In a Page

Read Next
It's not only the British who haven't been behaving well abroad; pictured here are German fans celebrating their team's latest victory  

Holiday snaps that bite back: What happens in Shagaluf no longer stays in Shagaluf

Ellen E Jones
Simon Laird (left) and Sister Simon Laird, featured in the BBC's The Secret History of Our Streets  

Estates of the nation: Let's hear it for the man in the street

Simmy Richman
Iraq crisis: How Saudi Arabia helped Isis take over the north of the country

How Saudi Arabia helped Isis take over northern Iraq

A speech by an ex-MI6 boss hints at a plan going back over a decade. In some areas, being Shia is akin to being a Jew in Nazi Germany, says Patrick Cockburn
The evolution of Andy Serkis: First Gollum, then King Kong - now the actor is swinging through the trees in Dawn of the Planet of the Apes

The evolution of Andy Serkis

First Gollum, then King Kong - now the actor is swinging through the trees in Dawn of the Planet of the Apes
You thought 'Benefits Street' was controversial: Follow-up documentary 'Immigrant Street' has got locals worried

You thought 'Benefits Street' was controversial...

Follow-up documentary 'Immigrant Street' has got locals worried
Refugee children from Central America let down by Washington's high ideals

Refugee children let down by Washington's high ideals

Democrats and Republicans refuse to set aside their differences to cope with the influx of desperate Central Americas, says Rupert Cornwell
Children's books are too white, says Laureate

Children's books are too white, says Laureate

Malorie Blackman appeals for a better ethnic mix of authors and characters and the illustrator Quentin Blake comes to the rescue
Blackest is the new black: Scientists have developed a material so dark that you can't see it...

Blackest is the new black

Scientists have developed a material so dark that you can't see it...
Matthew Barzun: America's diplomatic dude

Matthew Barzun: America's diplomatic dude

The US Ambassador to London holds 'jeans and beer' gigs at his official residence – it's all part of the job, he tells Chris Green
Meet the Quantified Selfers: From heart rates to happiness, there is little this fast-growing, self-tracking community won't monitor

Meet the 'Quantified Selfers'

From heart rates to happiness, there is little this fast-growing, self-tracking community won't monitor
Madani Younis: Five-star reviews are just the opening act for British theatre's first non-white artistic director

Five-star reviews are just the opening act for British theatre's first non-white artistic director

Madani Younis wants the neighbourhood to follow his work as closely as his audiences do
Mrs Brown and her boys: are they having a laugh?

Mrs Brown and her boys: are they having a laugh?

When it comes to national stereotyping, the Irish – among others – know it can pay to play up to outsiders' expectations, says DJ Taylor
Gavin Maxwell's bitter legacy: Was the otter man the wildlife champion he appeared to be?

Otter man Gavin Maxwell's bitter legacy

The aristocrat's eccentric devotion to his pets inspired a generation. But our greatest living nature writer believes his legacy has been quite toxic
Joanna Rowsell: The World Champion cyclist on breaking her collarbone, shattering her teeth - and dealing with alopecia

Joanna Rowsell: 'I wear my wig to look normal'

The World Champion cyclist on breaking her collarbone, shattering her teeth - and dealing with alopecia
Bill Granger recipes: Our chef gives raw ingredients a lift with his quick marinades

Bill Granger's quick and delicious marinades

Our chef's marinades are great for weekend barbecuing, but are also a delicious way of injecting flavour into, and breaking the monotony of, weekday meals
Germany vs Argentina World Cup 2014 preview: Why Brazilians don't love their neighbours Argentina any more

Anyone but Argentina – why Brazilians don’t love their neighbours any more

The hosts will be supporting Germany in today's World Cup final, reports Alex Bellos
The Open 2014: Time again to ask that major question - can Lee Westwood win at last?

The Open 2014

Time again to ask that major question - can Lee Westwood win at last?