Breastfeeding a child who can walk and talk is a polarising subject.

But when the evidence shows it has a number of benefits and very few drawbacks, you have to ask why some are so quick to judge.

Marion Taffe from Melbourne is currently breastfeeding her 33-month-old son Alexander. His older brother William breastfed until he was 16 months and some of that time was while Marion was pregnant.

She is well-informed of the health benefits of extended breastfeeding — she makes the point it's known simply as "breastfeeding" in many countries — but says the greatest advantage is using it as a calming tool.

Marion isn't ashamed about breastfeeding her 33-month-old but is aware people judge. ( Supplied: Marion Taffe )

"It's just a nice way to give him quiet time. We tend to stick to a schedule, morning and night," she said.

"Just having 10 or 20 minutes sitting quietly and calmly is really good for them. They're not watching TV, they have rhythmic breathing.

"I'm not one of these mums who will be at the park and their five-year-old will run up and start breastfeeding. But if that works for you, then great."

Marion makes it clear that isn't because she is ashamed, rather she doesn't like making other people feel uncomfortable.

"While I was pregnant and breastfeeding, I told someone it was probably why I felt so tired. She told me I had to stop breastfeeding straight away," she said.

"It was like I said I was trying to cut off my arm. The reaction freaked me out a bit and I realised not everyone is OK with this."

Marion said people needed to be more open minded, but she understood why it had an "ick factor" for some.

"We're brought up to see breasts as sexual things, and as babies turn into children who look like mini adults, seeing them sucking on a breast is uncomfortable for some people," she said.

"It's something that is wrapped up with marketing and media and images of breasts. But when you think about it, they are there for one purpose — to provide food."

Marion's breastfed William (L) when pregnant with Alexander. ( Supplied: Marion Taffe )

Marion said she always thought she would stop breastfeeding Alexander at three years of age — but he's showing no signs of stopping.

"People have funny rules in their head like once they can ask for it, they're too old for it," she said.

"The best advice I heard for everything parenting wise was do what works for you, and when it stops working for one of you or your family, change it. At the moment this still works for us."

Breastfeeding older children 'biologically normal'

Data recently published from Deakin University studied families between 2008 and 2010, and found at 18 months old 10 per cent of children were still breastfed, and that reduced to 1 per cent at 3.5 years.

Data from the 2006-2007 Longitudinal Study of Australian Children study shows at 24 months 5 per cent of children were still breastfed.

In 2012, Time Magazine stirred controversy with its provocative cover on attachment parenting. ( Supplied: Time Magazine )

La Trobe University breastfeeding expert Professor Lisa Amir said most families heard the message about the benefits of breastfeeding for six months, so they felt 12 months was a long time.

"The message that WHO [the World Health Organisation] recommends ongoing breastfeeding in the second year is rarely discussed," she said.

Breastfeeding counsellor with the Australian Breastfeeding Association Renee Kam said more women might breastfeed for longer if it was culturally acceptable.

"It's common place in other parts of the world to see older children breastfeeding and people just see it as normal," she said.

"But in westernised cultures like ours, it is something that is not seen and things that aren't seen tend to make people feel a bit uncomfortable ... It's biologically normal just not culturally."

Beneficial for mum and bub

Dr Amir said continuing breastfeeding meant optimal nutrition for the child, including providing long-chain fatty acids, immunoglobulins for immunity and a convenient way to settle an unhappy toddler.

"Also, breastfeeding provides food security for the toddler in case of an emergency, for example evacuation for fire or flood," she said.

"This might not be a true emergency, but could be a family getting stuck with a car breakdown or train disruption."

Susie Harrison from Gippsland in Victoria is currently breastfeeding her three-year-old son Phillip and has seen first-hand the nutritional benefits.

Susie Harrison is breastfeeding her three-year-old son ( Supplied: Susie Harrison )

"He's never had any antibiotics ... unlike my two older children who dealt with ear infections and tonsillitis."

Susie had planned to stop breastfeeding Phillip at 12 months but he was hard to settle at night "without his boobies," she laughs.

"Then I had heard about the benefits of prolonged breastfeeding even after the age of two, so when he showed no signs of weaning we just kept going."

A fussy eater, breastfeeding lets her know he is getting the nutrients he needs.

Ms Kam said there were also health benefits for the mother.

"Research shows there is a clear inverse dose-response relationship between breastfeeding and breast cancer risk," she said, adding that studies have shown that the longer a mother breastfeeds the lower chance she has of developing breast cancer.

Ms Kam said it was also beneficial for calming and comforting children.

"Children have described how breastfeeding can make them feel happy or loved or warm and cuddly," Ms Kam said.

The negatives might not be what you think

In 2012, Time Magazine stirred controversy with its provocative cover showing a mother breastfeeding her three-year-old son.

Larissa Waters breastfeeds her baby daughter as she puts forward a motion in the Senate. ( ABC News: Luke Stephenson )

The article dived into the world of attachment parenting and part of that philosophy is promoting extended breastfeeding.

When asked if continued breastfeeding could raise a more needy child, Ms Kam said there was "absolutely no evidence" that was the case.

"In fact there is some evidence to the contrary and anecdotally when I have been around older breastfeeding children and toddlers they tend to be very socially engaging."

She said the biggest hurdle of all wasn't anything to do with mum or bub, bur rather the social stigma.

"Even those close to you, like your spouse or mother, they might think breastfeeding is normal, but they might not be encouraging or supportive if breastfeeding a toddler or older child."

But while there is no research to support prolonged breastfeeding having a negative impact on mother or child, there are things mums need to be wary of.

For example, breastfeeding women will have to monitor their alcohol intake, and screen their medications to ensure no nasties are passed on through their milk.

Ms Kam said fidgeting may be "annoying" to the mother, as well as dealing with a toddler's demands for a feed.

"There might be times a toddler might want to feed a lot, and especially during those times mums might yearn for their own space," she said.