Identical and fraternal twins
Difference between identical and fraternal twins development
Identical twins develop through splitting of one fertilized egg (ovum) that both implants and leads to two babies having simillar genetic information. While, for the fraternal twins, two different eggs undergoes fertilization in the fallopian tube by two separate sperms.
Monozygotic twinning is the development of twins from one fertilized ovum/ egg that has split through a process of mitosis. The genetic information carried by the two ova after splitting is the same. This results in identical twins. The early embryo may split before implantation resulting in two separate placenta and amniotic sacs, implants in the womb then splits resulting in sharing of placenta but separate inner sacs or implants in the womb then splits later causing sharing of both inner sac and placenta. (Twins – identical and fraternal)
Two separate ova undergo fertilization by two separate sperms leading to fraternal twins. Around two in three sets of twins could be fraternal. The fraternal twins may have different genes but they are more alike than other siblings born at different times. They may be of the same or opposite sex with probability of outcome equal for each.
Ethical considerations with multifetal pregnancy and fertility drugs.
The main ethical issues include;
- Parental versus professional autonomy- the parent/ patient has the autonomy to decide the number of multiple embryones to receive. However, the physician has a responsibility to the welfare of the child(ren) future may conflict this autonomy.
- Non-maleficence- this is the professional responsibility of the physician not to cause harm to the patient during the procedure.
- Justice- the financial pressure relates to the request for multiple transfers of the embryo. Therefore, the less fortunate financialy are indirectly implicated in taking the risk of multiple pregnancies.(Law, 2003)