Can a virgin woman become pregnant without sex ?

Parthenogenesis (VIRGIN BIRTH) is a form of asexual reproduction in which an embryo is formed from an unfertilized egg. 

Normally, Fertilization occurs when a male sperm meets an ovum/egg from a female. At this point of sperm-egg/ovum interaction, a calcium spike occurs which causes ovum/egg activation, which is the first stage of embryo development. Several biochemical and structural changes occur which convert the fertilized ovum into a zygote implicating the beginning of  pregnancy. This leads to 9 months of joyful journey for a mother. The baby will have both maternal and paternal DNA.

But in rare cases, due to mutations in the ovum and division mistakes, a spontaneous calcium spike could cause the formation of an embryo without sperm/male DNA, eventually leading to pregnancy. This process is called Parthenogenesis (VIRGIN BIRTH). It occurs when a female reproduces without the involvement of males(sperms). In simple words, "a baby without daddy" 

This process is common in some species of insects, fishes, reptiles and plants, but is extremely rare in mammals. The possibility of human parthenogenesis has been a topic of scientific debate and speculation for many years. 

Apart from this, Parthenogenesis can also be induced artificially in some species by manipulating the eggs, such as applying heat shock or chemicals or hormone treatments to stimulate development.

In 1995, for the first time, a case of partial parthenogenesis was reported. A 3-year-old boy with asymmetrical facial features and mild learning difficulties was brought by his mother to the hospital. His blood workup had revealed that his white blood cells had 2 'X chromosomes' instead of '1 X and 1 Y chromosome' (Y chromosome represents maleness), the blood was characteristic of a female(XX) and not a male (XY) genotype. On further examination, it was found that his skin cells were genetically different from his blood cells. His skin cells revealed normal X and Y chromosomes characteristic of the male genotype (XY) [representing both maternal and paternal DNA].The best guess here is that immediately after fertilization, one of his mother's egg fused with neighboring unfertilized egg that was dividing parthenogenetically. This gave rise to a Partial Parthenogenetic boy with an unusual mixture of genetic material. 

TYPES OF PARTHENOGENESIS :- 

a) Haplodiploid Parthenogenesis - occurs in species with haplodiploid sex determination, where unfertilized eggs develop into haploid males and fertilized eggs develop into diploid females

b) Thelytokous Parthenogenesis - occurs when unfertilized eggs develop into females that are genetically identical to the mother

Parthenogenesis has also been studied for its potential applications in agriculture and biotechnology, such as creating seedless fruits and producing stem cells for medical research, cloning, gene editing, production of transgenic organisms. 

Some researchers have suggested that parthenogenesis could be used to generate patient-specific stem cells without a need for a donor embryo or risk of rejection and others have suggested that parthenogenesis could be used to produce offspring in cases where a male partner is not available or is infertile.