By 2040 it could be common to produce embryos from the skin cells of people of any age or gender

Genes

Cell donor

Nucleus

1

A non-reproductive human cell, such as a skin cell, is injected with genes that transform it into an induced pluripotent stem cell, capable of becoming any kind of specialised cell, including an egg or sperm.

Ovarian or

testicular

tissues

2

Chemical signals from ovarian or testicular tissues give the cell transformational instructions. Before it can become a mature egg or sperm it must go through a process that halves its chromosomes from 46 to 23.

3

Sperm and eggs may be produced from both male and female donors and can produce embryos to be implanted or frozen for future use. A single donor could even provide both sperm and egg, creating a ‘unibaby’.

Ovarian or

testicular

tissues

Cell donor

Genes

Nucleus

3

2

1

A non-reproductive human cell, such as a skin cell, is injected with genes that transform it into an induced pluripotent stem cell, capable of becoming any kind of specialised cell, including an egg or sperm.

Chemical signals from ovarian or testicular tissues give the cell transformational instructions. Before it can become a mature egg or sperm it must go through a process that halves its chromosomes from 46 to 23.

Sperm and eggs may be produced from both male and female donors and can produce embryos to be implanted or frozen for future use. A single donor could even provide both sperm and egg, creating a ‘unibaby’.