The lifestyle a person shares with their partner has a greater influence on their chances of becoming obese than their upbringing, research suggests.

By middle age, the choices made by couples - including those linked to diet and exercise - will have a much greater impact than the lifestyle they shared with their siblings and parents when growing up, the study found.

Researchers said the study will help scientists better understand the links between obesity, genetics and lifestyle.

The team analysed data provided by 20,000 people from Scottish families.

The information was originally gathered as part of the Generation Scotland project, a national resource of health data that helps researchers to investigate genetic links to health conditions.

Scientists compared people's family genetics and home environments in childhood and adulthood and related those to measures linked to health and obesity.