People receiving kidneys from living donors have concerns the donors really want to go ahead with the procedure.
Donors agree to undergo major surgery
A study of 11 pairs of donors and recipients found none of the donors had any concerns about the procedure.
But recipients, all of whom were either relations or partners of the donors, wanted to talk things through first.
However, the Cardiff University researchers found both parties were positive about the experience following the transplant.
In all the cases studied, all the donors decided instantly to go ahead.
Every one said they were donating to restore the health of the recipient.
Those who were husbands and wives said they were also keen to be able to have a normal life together.
But Paul Gill, from the University's School of Nursing, said: "Recipients originally showed caution because they were concerned for their donor's health.
"They only agreed to accept after establishing that it was something the donor genuinely wanted to do."
After the transplant, both parties felt very positive.
Donors generally made a good recovery and were back at work within 10 to 12 weeks.
They also tended to downplay what they had done, making statements like "it was nothing special", or "anyone would have done the same".
Mr Gill said: "Recipients reported that their lives had been transformed by the transplant, experiencing significant improvements in their general health and ability to do things they hadn't been able to do in years, such as exercising, driving and holidaying abroad.
"And donors subsequently felt an immense sense of personal satisfaction from donating."
The findings will be presented to the British Sociological Association's Medical Sociology Group annual conference in September at the University of York.
'Most operations successful'
Caroline Rijnenberg, who received a kidney from her husband Ian, urged people not to be afraid of a living transplant.
"It's been such a positive thing for both of us from the day Ian decided to do it."
A spokeswoman for the National Kidney Research Fund said: "Due to the massive shortage of organ donors, many people find that an organ from a living donor represents their best hope of getting a transplant.
"In most cases, living donor transplants are between close relatives such as parent and child or between siblings and it's only natural that both parties may want to talk it through."
She added: "With many kidney patients facing years on the transplant waiting list, relatives are often desperate to help by volunteering to donate one of their kidneys.
"It is quite common for the recipient to perhaps feel some guilt or concern about their relatives' health because it is an incredibly kind gesture.
"Happily though, around 93% of living donor operations are successful, and both patients usually recover quickly"