Distinguishing between gay and straight orientation is greatly aided by the fact that adult men and women tend to be markedly different from each other. Upon seeing a random adult, the vast majority of the time we know instantly if they are male or female. Seeing them naked would clarify most of the remaining cases. The exceptions (intersex, transgender, etc.) are so rare that the typical person feels confident in their orientation without even thinking about their degree of attraction to them. Bisexuality is having some attraction to both Column A and Column B.
In gauging an attraction to children versus adults, the situation is entirely different. At any given time, the population contains people at every stage from infant to adult, and the very same individual progresses from one end to the other over time. There are different ways of trying to divide this age range into discrete categories. There are 5 <Tanner Stages>. Some people speak of prepubescents, pubescents, and postpubescents, defining 3 stages. When diagnosing sexual attraction based on age, a total of 4 categories are sometimes used: pedophiles, hebephiles, ephebophiles, and teleiophiles. The number of categories is arbitrary because age is fundamentally a continuous spectrum.
For any given person, there is likely to be a sort of bell curve of attraction with age. For an example of a research paper showing this, see <Blanchard, et al>. For pedophiles it might be centered on Tanner Stage 1, and for ordinary men at Stage 5. The Tanner scale focuses on the changes right around puberty. There are further distinctions in the extreme categories -- showing that physical sexual development is not the whole story by any means. Some ordinary men will have a curve centered at age 16, and others at age 30, and a few gerontophiles at much older ages. Within pedophiles, some are most attracted to age 9 and others to age 3.
In <this post> I addressed how self-identification as a pedophile is partly related to the attraction characteristics and partly to how a person feels about it. In that post I dealt with just two categories, "adult" and "child" -- which of course was a major simplification.
People people with a significant attraction to Tanner Stages 4 and below can show up online as self-identified pedophiles. One way of thinking about a non-exclusive pedophile is one with a significant attraction to Tanner Stage 5.
The attraction patterns vary a great deal aside from what age they are centered on. Some are attracted to a broad range, and others to a narrow one. Gender of course defines two separate curves, not just one. Several people writing to Virtuous Pedophiles have reported an attraction to pubescent boys and to adult women -- but no attraction to girls or to adult men. The opposite pattern -- adult men and pubescent girls -- has never been reported to us. Some pedophiles report their attraction as primarily romantic, others as primarily sexual. Sometimes these will vary depending on age. A pattern that has been reported multiple times is a sexual attraction to girls from perhaps 9 to 13 years of age, but a romantic attraction that covers a wider range, starting perhaps at age 4.
Scientific studies necessarily focus on just a few groups, defined by just a few characteristics. They need large numbers of people to make meaningful comparisons and need to simplify for that purpose. However, reading those studies will tend to make a person lose sight of the many unusual instances and patterns that exist among real people.
The differences in attraction patterns involving age is one more aspect to how much variety there is among pedophiles.