can identical twins have different religious beliefs?

[Confused Ape]

I'm having problems accepting this, as I'd imagine others here also would.
It's hard for me to entertain the notion of a god gene.
Nature couldn't create it ... It's a paradox within itself. It can never become a scientic fact.
Unless god inserted it " in the beggining" and then let nature do its thing.
If that's the case, we're all fucked and I've got a front row seat in hell.
I imagine Stimbo would be next to me! Hehe

All it means is that there's a genetic component to people's susceptibility for religious belief. Humans developed religious belief long before the God of the Bible was invented. After all, there were much earlier religions and the very first one could have been shamanism.

Shamanism and Shamanic Practises

Shamanism (/ˈʃɑːmən/ shah-mən or /ˈʃeɪmən/ shay-mən) is a practice that involves a practitioner reaching altered states of consciousness in order to encounter and interact with the spirit world and channel these transcendental energies into this world.[2] A shaman is a person regarded as having access to, and influence in, the world of benevolent and malevolent spirits, who typically enters into a trance state during a ritual, and practices divination and healing.[3]

Shamans gain knowledge and the power to heal by entering into the spiritual world or dimension.

Shamanic practices may originate as early as the Paleolithic, predating all organized religions,[83][84] and certainly as early as the Neolithic period.[84] Early anthropologist studies theorise that shamanism developed as a magic practice to ensure a successful hunt or gathering of food. Evidence in caves and drawings on walls support indications that shamanism started during the Paleolithic era. One such picture featured a half-animal, with the face and legs of a man, with antlers and a tail of a stag.[85]

Archaeological evidence exists for Mesolithic shamanism. The oldest known Shaman grave in the world is located in the Czech Republic at Dolni Vestonice (National Geographic No 174 October 1988). This grave site was evidence of a female shaman.

In November 2008, researchers from the Hebrew University of Jerusalem announced the discovery of a 12,000-year-old site in Israel that is perceived as one of the earliest known shaman burials.

Humans aren't the only animals which go in for altered states of consciousness. I found an article giving a number of examples but I'm only going to quote the ones involving chimpanzees - they're our closest relatives and we share a common ancestor with them.

Animals on Psychedelics: Survival of the Trippiest

In 2006, Jane Goodall and Marc Bekoff visited the Mona Chimpanzee Sanctuary in Spain. They met a chimp named Marco who dances during thunderstorms with such abandon that, as Bekoff explains it: "He appears to be in a trance." Goodall has witnessed other chimps, usually adult males, enacting the same rituals near waterfalls. According to an article Bekoff wrote for New Scientists : "She described a chimpanzee approaching one of these falls with slightly bristled hair, a sign of heightened arousal. ‘As he gets closer, and the roar of the waterfall gets louder, his pace quickens, his hair becomes fully erect, and upon reaching the stream he performs a magnificent display close to the foot of the falls,' she describes. ‘Standing upright, he sways rhythmically from foot to foot, stamping in the shallow, rushing water, picking up and hurling great rocks. Sometimes he climbs up slender vines that hang down from the trees high above and swings out into the spray of the falling water. This ‘waterfall dance' may last ten to fifteen minutes.'" But dancing, while an effective method for altering one's consciousness, is perhaps the long way round.

This doesn't mean that chimpanzees have invented religion, of course, but the behaviour in the two examples could indicate something about it's pre-human roots.

Nobody knows why the human brain evolved for religious belief but it's likely that it was selected for because it was useful in the dim and distant past. I found an interesting article on the Harvard Magazine website - The Placebo Phenomenon

But researchers have found that placebo treatments—interventions with no active drug ingredients—can stimulate real physiological responses, from changes in heart rate and blood pressure to chemical activity in the brain, in cases involving pain, depression, anxiety, fatigue, and even some symptoms of Parkinson’s.

The challenge now, says Kaptchuk, is to uncover the mechanisms behind these physiological responses—what is happening in our bodies, in our brains, in the method of placebo delivery (pill or needle, for example), even in the room where placebo treatments are administered (are the physical surroundings calming? is the doctor caring or curt?). The placebo effect is actually many effects woven together—some stronger than others—and that’s what Kaptchuk hopes his “pill versus needle” study shows. The experiment, among the first to tease apart the components of placebo response, shows that the methods of placebo administration are as important as the administration itself, he explains.

Maybe belief in shamanic practises acted as a kind of placebo effect in the days when there was nothing more than herbal remedies. There's an interesting phenomenon called Vooddo Death which has a modern explanation.

Voodoo death, a term coined by Walter Cannon in 1942 also known as psychogenic death or psychosomatic death, is the phenomenon of sudden death as brought about by a strong emotional shock, such as fear. The anomaly is recognized as "psychosomatic" in that death is caused by an emotional response—often fear—to some suggested outside force. Voodoo death is particularly noted in native societies, and concentration or prisoner of war camps, but the condition is not specific to any particular culture.[1]

Since 1942, scientists have discovered many more of the processes involved in the effect of stress upon the body, such as the region of the brain called the amygdala. The series of events by which a sensory stimulus is introduced to the mind, and the amygdala processes the emotion of fear which follows is called the "vision-to-fear pathway," or the "auditory-to-fear pathway," depending on the stimulus.

The generally recognized sequence of events, as enumerated by Esther M. Sternberg, MD, in 2002, stands as follows: various chemicals and electrical impulses are released that are transmitted by nerve fibers. Simultaneously, hormones are excreted from the brain, adrenal and pituitary glands in response to stress on the system. Cardiac arrhythmias are often the result of an overabundance of these hormones on the system.[3]

In 1981, Wylie Vale, PhD, discovered corticotrophin, the brain's hypothalamic stress hormone, or CRH: this hormone secreted by the hypothalamus coordinates with "the brain stem adrenaline centers involved in initiation of the sympathetic response ... to cause a massive release of both adrenaline-like nerve chemicals and stress hormones. Together these might well cause illness, including loss of appetite, weakness, cardiac arrhythmias, and even vascular collapse that could result in death."[3]

Martin A. Samuels, MD, elaborates further on still another process of death, stating that with the release of adrenaline and an increased heart rate, sometimes catecholamines, stress hormones, will build up, leading to calcium channels opening and remaining open, resulting in an overflow of calcium into the system, killing off cells.[4]

Maybe belief that spirits can heal reduced worries about dying so people had a better chance of recovering from illnesses and injuries which it was possible to recover from in Paleolithic/Neolithic times. The believers who had the 'belief genes' could have been more successful in passing their genes on.