I am unsure if this is the right subreddit for this question but I am writing a paper on the use of twin and adoption studies to gauge the heritability of intelligence. I want to know 1) what was/were the purpose(s) of twin experiments by the Nazi's and Mengele, and 2) can any comparisons be made between the studies then and the studies now?
The "purpose" was to benefit the genetics of the Aryan race. If Aryan women could assuredly give birth the blonde hair blue eyed children then the master race would be "saved." Twins gave a control group. Mengele did not just do genetic tests on twins though; he also tried to create Siamese twins and painful blood-taking from dwarves and cripples, sometimes daily, because dwarves and cripples showed the deterioration of the Jewish race. Other camps also did hypothermia, high altitude, mustard gas, and many other experiments. Some with the "purpose" being more legitimate, such as the gangrene testing for war field use.
It is actually a debated subject if current researchers should ethically use the results from Nazi medical experiments, due to how the results were obtained. Any self respecting doctor would never use them. That doesn't stop some, like the doctors at Gitmo, from advising the CIA to use saline solution instead of water to water board detainees. The Nuremberg Code lists guidelines for human experimentation; there were made after the subsequent Nuremberg Trials.
This is a fascinating topic, and you should look into not just Mengele, but also Dr. Carl Clauberg, Dr. Karl Brandt, Dr. Herta Oberheuser, as well as the Doctor's Trial. This could drastically help your research.
The purposes of the Nazi experimentation on twins were many, and not all researchers had the same goals.
Mengele had experiments both physical and psychological, these are some, but not all.
I think these acts are fascinating in their morbidity, how the structures of the Holocaust enabled people to estrange themselves from their emotions and compassion.
His work had little to do with modern science. Mengele acted as a sociopath, where "interest" rather than scientific inquiry guided his experiments. He acted as a monster in clear violation of the Hippocratic Oath. Beyond some rudimentary similarities, his experiments aren't close to similar to the modern way of doing science. Mengele committed mass murder on unscientific grounds on nothing but hunches and whims.