Arguments against gene therapy and genetic engineering
The new child is used as a means to an end, ie to cure the sibling.
The new child has no choice in this process and they cannot give their agreement.
Some people suggest that it goes against nature, and that scientists are 'playing God'.
Somatic cell therapy
Scientists believe that changed genes in somatic cells do not pass to the sex cells, but if this did happen the changes would inadvertently be passed to future generations.
Some people suggest that it goes against nature, and some would suggest that scientists are 'playing God'.
Germ line therapy
Unlike other medicines, the negative effects cannot be understood because they rest with future generations.
The people affected by germ line therapy who will be born in the future have not agreed to this therapy.
Who decides which conditions require treatment? It could be tempting to also 'cure' conditions like baldness and obesity. This would be improvement, not treatment.
Pre-Implantation Genetic Diagnosis (PGD): for diseases
Those living with conditions or diseases could feel inferior. It might create a society where the disabled, or those suffering from diseases, are seen as less than fully human.
Some view the destruction of embryos as murder because they are human individuals.
Some suggest it is for the parents' convenience. It is not because of the child's wellbeing.
Pre-Implantation Genetic Screening (PGS): screening for gender
Parents should love their children, whatever the gender.
It could lead to gender imbalance in society, ie too many boys or girls.
Selecting for one gender might suggest that one gender is more important, which could lead to sexism in society. An imbalance in the numbers of men and women may also leave one gender with less opportunity to find a partner.
Enhancement: for qualities
Altering genes to improve strength, beauty or intelligence undermines the moral and legal idea that all humans are equal.
The technology could be misused. In the future, 'superhuman' soldiers with certain physical and intellectual characteristics could be created. These individuals would have no say in this.
Further inequality in society – those who are genetically engineered and those who are not.
The embryos that are destroyed after the research are human individuals. This is murder.
Research on embryos treats them as an object. It removes their value.
The genetic material discovered could be patented by drug companies and made available only to the wealthy.