Breast milk is a complex substance, and breastfeeding is more complicated. We are still a long way from completely rebuilding it.

It is one thing to produce chicken nuggets or even whole steaks through cell agriculture, but it is another thing to provide developing children with all the nutrients they need for the first year of life.

But cell-cultured breast milk will soon help non-breastfeeding parents who want a better choice than existing milk-based formulas.

Breast milk farming and farmed meat production have many similarities. The basic steps are as follows.

First, you need some milk-producing cells that line the ducts of the breast. These "breast epithelial cells" can be cultured from donated milk.

Then grow the cells in flasks filled with nutrients to allow them to multiply.

Once you have enough cells to behave like healthy breast tissue, you can transfer them to a bioreactor (a larger nutrient container) similar in structure to the breast duct.

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Next, you add a hormone called prolactin to the bioreactor. This allows the cells to give the green light for lactation on the one hand, and to absorb nutrients on the other.

Finally, you perform quality control and safety inspections.

Finally, you can add more supplements that are naturally present in breast milk, such as beneficial antibodies and bacteria, and even immune cells and stem cells.

Breast milk keeps the brain, immune system and metabolism in the process of life-long improvement of cognitive function, reduction of infections and chronic diseases. For premature babies or sick babies, the value of breast milk is particularly prominent.

Breast milk contains an optimal balance of water, carbohydrates, fats, proteins and micronutrients, as well as a mixture of maternal immune cells, stem cells, antibodies and healthy bacteria, which are the seeds of children’s gut microbiota.

Breast milk will also change over time to meet the changing needs of developing children. It can even directly help the infection. When a pathogen from the upper respiratory tract of a baby enters the mammary duct, the mother can initiate an immune response and feed back targeted immune cells and antibodies to the child.

For various reasons, breastfeeding is not an option for many new parents. According to the latest report from the Australian Bureau of Statistics (covering the 2017-18 fiscal year), only 29% of 6-month-old babies are exclusively breastfed, but more than half (53%) of babies are not introduced into solid foods.

This indicates that about a quarter of babies are feeding formula milk. From a nutritional point of view, infant formula is completely acceptable, but it cannot replicate the complexity of real products.

Most infant formulas are made from milk, which is best for calves rather than human babies, and lacks more subtle health-promoting factors, such as mother’s antibodies and beneficial bacteria.

In addition, recent calculations indicate that feeding infant formula milk produces more carbon emissions than breastfeeding. This shows that breastfeeding mothers should eat 500 more calories, even when the mother is eating animal food.

Donated milk is another option for breastfeeding, but it is difficult to obtain, and milk banks give priority to premature babies and sick babies. In the 2020-21 fiscal year, the Australian Red Cross Blood for Life recorded 2,320 liters of breast milk donated to more than 1,000 vulnerable babies.

There are also online breast milk markets on sites such as Facebook and Craigslist. These are unregulated, are potential sources of infectious diseases and make desperate parents vulnerable to exploitation.

Although no cell-cultured breast milk is currently on the market, several companies are studying it. Some of the companies closest to launching products include US BIOMILQ, Israel BioMilk, and US-Singapore TurtleTree Labs.

In Australia, stem cell scientist and entrepreneur Luis Malaver-Ortega founded a company called Me&Food Tech to produce breast milk using a new cell-based technology.

When will these products be launched? It's hard to say accurately.

Before the large-scale production of cell culture breast milk companies, there are obvious obstacles in basic research and supervision that need to be overcome. But private investment in this industry is growing rapidly, and the interest of university researchers is also growing rapidly.

Ruth Purcell is a PhD researcher at the University of Melbourne. Find Ruth on Twitter @RuthAmyPurcell

Bianca Le is a cell biologist and an honorary researcher in agriculture and food at the University of Melbourne. Find Bianca on Twitter @drbiancale

A version of this article was originally published in the conversation and republished here with permission. The conversation can be found on Twitter @ConversationUS