This is a problem more prevalent in the western countries than here, but nevertheless an important issue.
http://www.berzinarchives.com/web/en/archives/approaching_buddhism/introduction/dharma_lite.html
Tibetan Buddhism follows the Indian tradition and all Indian traditions take for granted belief in rebirth. Even if traditional Buddhist seekers do not have a deep understanding of what takes rebirth or how rebirth works, still they have grown up with the idea of rebirth as a cultural given. They need merely to have their understandings refined, but do not need to become convinced in the existence of rebirth. Therefore, texts on the graded stages of the path (lam-rim) do not even mention the topic of gaining conviction in the existence of rebirth.
Without rebirth, the discussion of mind having no beginning and no end becomes meaningless. Without beginningless and endless mind, the entire presentation of karma falls apart. This is because the karmic results of our actions most frequently do not ripen in the same lifetime in which we commit the actions. Without the presentation of karmic cause and effect over the span of many lifetimes, the discussion of the voidness of cause and effect and of dependent arising likewise falls apart.
Moreover, in terms of the three scopes of lam-rim motivation, how can we sincerely aim for benefiting future lives without belief in the existence of future lives? How can we sincerely aim for gaining liberation from uncontrollably recurring rebirth (samsara) without belief in rebirth? How can we sincerely aim for enlightenment and the ability to help others gain liberation from rebirth without belief that rebirth is a fact?
In terms of bodhichitta meditation, how can we sincerely recognize all beings as having been our mothers in previous lives without believing in previous lives? In terms of anuttarayoga tantra, how can we sincerely meditate in analogy with death, bardo, and rebirth to purify ourselves of uncontrollably experiencing them if we do not believe that bardo and rebirth occur?
Thus, it is clearly evident that rebirth is a cornerstone for a large and crucial portion of the Dharma teachings.
Most Westerners come to Dharma without prior belief in rebirth. Many approach the study and practice of Dharma as a method for improving the quality of this lifetime, especially in terms of overcoming psychological and emotional problems. This attitude reduces Dharma to an Asian form of psychotherapy.
I have coined the term Dharma-Lite for this approach to Buddhist Dharma, analogous to "CocaCola-Lite." It is a weakened version, not as strong as "The Real Thing." The traditional approach to Dharma - which includes not only discussion of rebirth, but also the presentation of the hells and the rest of the six realms of existence - I have termed The Real Thing Dharma.
There are two ways to practice Dharma-Lite.
Therefore, we need to proceed with great care if we find that, at our present level of spiritual development and understanding, Dharma-Lite is the drink for us.
Buddhism becomes Dharma-Lite when
The Real Thing Dharma is the authentic traditional practice of Buddhism, in which