1. The statement "The only source of human stem cells are the embryos at the blastocyst stage" is not correct. While embryos at the blastocyst stage are one source of human stem cells, there are other sources as well. Stem cells can also be derived from adult tissues, such as bone marrow, adipose tissue, and umbilical cord blood.

2. The statement "The stem cells can be derived without causing destruction to blastocysts" is incorrect. To obtain embryonic stem cells, it is necessary to destroy the blastocyst, which is a stage of early development. This process raises ethical concerns and has been a topic of debate.

3. The statement "The stem cells can regenerate themselves in vitro virtually forever" is correct. Stem cells have the unique ability to divide and renew themselves, a process known as self-renewal. This characteristic allows them to continually generate more stem cells and maintain their undifferentiated state, making them a valuable tool for research and potential therapies.

4. The statement "Indian research centers also created a few cell lines which can be developed into many types of tissues" is correct. India has made significant advancements in stem cell research, and several research centers have successfully created stem cell lines that have the potential to differentiate into various types of tissues. These cell lines hold promise for future therapeutic applications.

Therefore, the correct statements are 3 and 4.