Anna Veiga Lluch (1956-) is a Spanish biologist and university professor, specialized in clinical embryology, reproductive genetics, the study of embryonic and pluripotent stem cells and bioethics.  
She was the "scientific" mother of the first child born by in vitro fertilization in Spain. Since then, the study of stem cells has advanced greatly and has opened up a world of possibilities. 

Read the following text and answer the questions:

Stem cells are the raw material of the body; from them all other cells with specialized functions are generated. Stem cells divide to form more cells called daughter cells, which become new stem cells or specialized cells (differentiation) with a more specific function, such as blood cells, brain cells, heart muscle cells or bone cells. No other cell in the body has the natural ability to generate new cell types.

Stem cells may help to do the following:
- Understand more about how diseases occur. 
- Generate healthy cells to replace cells affected by disease (regenerative medicine). Stem cells can be targeted to become specific cells that can be used in people to regenerate and repair tissues that disease has damaged or affected.
- Test the safety and efficacy of new drugs. Before using experimental drugs in people, researchers can use some types of stem cells to test their safety and quality.

There are several sources of stem cells:
- Embryonic stem cells. These stem cells come from embryos that are 3 to 5 days old. These are pluripotent stem cells, which means that they can divide into more stem cells or can become any type of cell in the body. 
- Adult stem cells. These stem cells are found in small amounts in most adult tissues, such as bone marrow or fat. They have a more limited ability to generate different cells in the body.
- Adult cells modified to have the properties of embryonic stem cells. Scientists have successfully transformed normal adult cells into stem cells by genetic reprogramming. 
. Perinatal stem cells. Researchers have discovered stem cells in amniotic fluid as well as in umbilical cord blood. These stem cells have the ability to develop into specialized cells.

Embrionic stem cells are obtained from early-stage embryos, a group of cells that form when eggs are fertilized with sperm in an in vitro fertilization clinic. Because human embryonic stem cells are extracted from human embryos, several questions and issues have been raised about the ethics of embryonic stem cell research.
                          Source: Mayo Clinic (adapted)

a) What are stem cells?  

b) What are the characteristics of pluripotent stem cells? Where do they come from? 

c) What medical applications can the use of stem cells have? What type of stem cells do you think are most appropriate to use in these applications?

d) What do you think about the use of embryonic stem cells in research? Have a class discussion on this topic.