Government-funded research by the Policy Studies Institute found women and Asian students were less likely than other groups to take out student loans.
A large percentage of students who declined a loan did so because of fear of debt, raising concerns about the potential deterrent effect of the Government's decision to abolish university maintenance grants and replace them with bigger student loans.
But researchers did find that poorer students were more likely to take out a loan than their better-off counterparts - suggesting that any deterrent effect of Labour's new student loans scheme may not be based on income alone.
And researchers suggest that easier repayment terms, as proposed by ministers, could offset fears about running up large debts.
The report says: "The decision about whether to take out a student loan is not driven only by financial need or the perception of financial advantage.
"There appears to be a group of students who are averse to the idea of debt, however economically rational it may be to borrow.
"Nearly two-thirds of students who chose not to take out a loan in 1995-96 cited concerns about borrowing as the main reason for their decision."
The report added: "Now that a much greater proportion of student finances is to come from loans, these negative attitudes towards borrowing may deter some groups of young people from entering higher education."
Researchers Joan Payne and Claire Callender interviewed nearly 2,000 students in 72 universities and colleges for the study. They found people from Asian backgrounds about half as likely to take out a loan as white students, while women in general were about 10 per cent less likely to take out a loan than men.
The report said: "Women were less likely to take out a student loan than men. This may reflect gender differences in attitudes to debt. Asian students were substantially less likely to take out student loans than members of other ethnic groups. Sample numbers were too small to be sure of the reasons for this, though it may be linked to lack of knowledge about student loans. "
Other findings suggested that some well-off students were taking out the interest-free loans for financial reasons - adding fuel to speculation that some may simply invest their subsidised loans.
But researchers found one in six students did not receive the full contribution that their parents were supposed to pay towards their maintenance. The problem was worse among students aged 20 to 24, where one in four received less than expected from their parents.
The figure raises concerns about the ability or willingness of parents to pay the new university tuition fees, which must be paid by undergraduates from next year.
Ministers have insisted that there is no reason for parents not to pay, but student leaders say that this is already a serious problem for some undergraduates.
Universities will be responsible for collecting tuition fees, under plans being drawn up by ministers. They will also have to decide what to do with students whose parents cannot, or will not, pay the fees.