We know for sure that Maryam, mother of Prophet Essa (pbuh) gave birth to him as a virgin mother. This was a purely miraculous event because Allah Almighty ordained it as such, and as He states in His Final Message, the birth of Prophet Essa was similar to the birth of the first Prophet, Adam. Both of them did not have a father. Adam had neither a father nor a mother while Essa had only a virgin mother. This is clear and confirmed.
"Lo! the likeness of Jesus with Allah is as the likeness of Adam. He created him of dust, then He said unto him: Be! and he is." (3:59) Surah Al-Imran.
Shocking as it may sound, nowadays there are incidents of Christian nuns getting pregnant. As we know, concepts of morality have fallen much in non-Muslim countries and permissibility is constantly on the rise. For Christian clerics - bishops, priests, nuns etc. - celibacy is a must and thus they are not allowed to marry. Considering the liberal values that surround them, they often find it hard to indefinitely continue respecting their covenant and maintaining their chastity after embracing monasticism. To make matters worse, majority of them don't want to acknowledge the truth when they consummate their relationships. Stories of philandering male Christian clerics are very common mainly involving sexual abuse of underage children - both boys and girls. And now, occurrences of Christian nuns indulging in physical intimacy are getting just as recurrent.
It's clear in the Glorious Quran that Virgin Maryam's case was unique as decreed by Allah Almighty. Her exemplary character made her extraordinary and The Almighty placed her above all other women. This too has been confirmed in the Quran.
"And when the angels said: O Mary! Lo! Allah hath chosen thee and made thee pure, and hath preferred thee above (all) the women of creation." (3:42) Surah Al-Imran.
As submitters and followers of the Monotheistic Faith, we must never overlook the fact that Allah is the All-Powerful and when He decrees a thing, He only says "Be" and it is. Nothing is impossible for Him nor is the happening of any phenomenon difficult for Him to actualize. Just as important to remember is that according to His standard Laws, He does not bestow His miracles on just any commoner. He only selects the very special ones. And He has already informed us that after the Final Messenger, Muhammed (peace and blessings be on him), there will be no other chosen persons entrusted with similar responsibilities. Only the Noble Quran will be in this world for guidance until the Last Day and whoever reaches out to it will work to benefit their own souls. Thus, after the seal of Prophethood, there is no question of anyone in the world being vouchsafed with miracles as granted to some Prophets and certain members of their families. To presume that would be a wild speculation for which we will have to answer to Him on the Day of Judgment.
Coming to the other point - rising incidents of pregnancy among Christian nuns - while some admit breaking their pledge, many more claim they don't know how they conceived. They speak to the affect that one fine day they suddenly experienced cramps in their stomach, they were sent to the hospital where it was discovered to their surprise that they were pregnant and consequently they gave birth. They don't specifically say they are virgins, but neither do they acknowledge they aren't virgins any longer, discreetly implying virgin birth as in the case of Virgin Maryam. Such an attitude is extremely impertinent. It deepens their transgression, adding dishonesty alongside lewdness. After being aware of their lustful conduct caving in to their carnal desires, trying to cover it up by drawing parallels with the chosen persons of Allah Almighty is NO small violation. These women who become nuns are ordinary females like the rest. There is absolutely no possibility of any miracles being bestowed on them by the Divine Power.
The most recent incident happened in Italy in January 2014 where a Latin American nun gave birth claiming she never knew she was pregnant until one day when she suddenly felt pain in her stomach and was taken to hospital where she gave birth. Ridiculous! As if pregnancy is an inflammation that flares up unexpectedly like appendix. Pregnancy occurs gradually with dozens of signs and biological changes until one gives birth. It starts with morning sickness in most women. Even if some don't experience sickness, the tummy SURELY grows gradually and after the sixth or seventh month looks very huge which definitely cannot go unnoticed neither by the pregnant woman nor by the people around her. The body gains weight. The monthly menstruation cycle stops. Various women experience different additional symptoms. By the time a woman is ready to give birth after nine long months and goes through labor which can often be prolonged for several hours, she certainly cannot claim she wasn't aware of what was happening to her body since the past so many months. That's just impossible.
Even in the case of Virgin Maryam, as confirmed in the Noble Quran (Verses 19:16-23), the Virgin birth of her baby didn't come abruptly as a surprise within one or two hours of notice. The angel sent by The Almighty informed her that she was to have a "faultless son" .. and when Virgin Maryam expressed her surprise how that could happen, the angel mentioned that nothing is impossible for Allah. She knew long before giving birth that she was pregnant, and she withdrew to a secluded place. She went through the stress of childbirth and prior to giving birth, the pangs of childbirth were excruciating. It's what we call, the state of labor.
The virgin birth of Prophet Essa (pbuh) is described very eloquently in Surah 19 (Maryam), Verses 16 to 23, quoted below:
"And make mention of Mary in the Scripture, when she had withdrawn from her people to a chamber looking East, 19:16.
And had chosen seclusion from them. Then We sent unto her Our Spirit and it assumed for her the likeness of a perfect man. 19:17.
And had chosen seclusion from them. Then We sent unto her Our Spirit and it assumed for her the likeness of a perfect man. -- 19:18.
He said: I am only a messenger of thy Lord, that I may bestow on thee a faultless son. 19:19.
She said: How can I have a son when no mortal hath touched me, neither have I been unchaste ? 19:20.
He said: So (it will be). Thy Lord saith: It is easy for Me. And (it will be) that We may make of him a revelation for mankind and a mercy from Us, and it is a thing ordained. 19:21.
And she conceived him, and she withdrew with him to a far place. 19:22.
And the pangs of childbirth drove her unto the trunk of the palm-tree. She said: Oh, would that I had died ere this and had become a thing of naught, forgotten!" 19:23.
Here is the ludicrous and untruthful story of the Italian nun at Yahoo News: Shocked Italian nun gives birth to a baby boy.
Concerning this incident, a local pastor also supported the nun's phoney claims, falsely testifying in favor for her that she didn't know she was pregnant. Again, if you read the article, it doesn't address her as a virgin after delivering the baby in so many words, but neither does it state that she wasn't a virgin any longer.
More absurdity comes from the attitude of the modern media. Generally their skepticism promptly derides every miracle of Allah Almighty stated in the Noble Quran. Almost all modernists (and the current Western media represents them) do not believe in the Virgin birth of Prophet Essa (on whom be peace). Yet the same sources struggle to construct biological or medical reasons for rare virgin births when a female Christian cleric gets pregnant.
The article tries to throw dust into the eyes of the readers by quoting a survey (the authenticity of which is far from confirmed) by the British Medical Journal (BMJ) which said that in America "one in 200 US women claim to have given birth without ever having had sexual intercourse." Mark the word, BMJ itself uses the term "claim" which implies it is not sure whether or not these women are speaking the truth. Also it does not say "virgin" birth. It says birth without having sexual intercourse which can refer to several different types of artificial insemination. If one out of every 200 females gave virgin birth without the surrogate process, that would suggest that this isn't a very rare occurrence. In that case surely almost all of us would have known at least one or two persons in our entire lives who had experienced this phenomenon. But surely again, none of us know of any common female who has given birth in a state of virginity without artificial methods of fertilization.
Thus, answering the query: Is virgin birth also possible with just about any human female in the world, any time? The answer is certainly NO. Attaining piety in a fraudulently manner for the sake of concealing loose morals and avoiding its embarrassments is a lowly practice. Such persons end up making themselves still more dishonorable when they make light of the special miracles of Allah Almighty which He bestowed only on His chosen slaves. These unconscientious persons need to keep in mind a very simple fact: While they may mislead or win the support of some of their fellow human beings, they can NEVER mislead nor gain the favor of The Almighty, The One and Only.