SAN FRANCISCO - SOCIAL network site Facebook will press members to declare whether they are male or female, seeking to end the grammatical device that leads the site to refer to individual users as 'they' or 'themself'.

The Internet phenomenon, which boasts 80 million users worldwide, exploded in popularity over the past year as a convenient way for Web users to communicate and share personal details with selected groups of friends or acquaintances.

But grammatical errors in the automated messages Facebook uses to personalise pronouns when members share information with their friends have proliferated since the site expanded from English-only into 15 new languages in recent months.

'We've gotten feedback from translators and users in other countries that translations wind up being too confusing when people have not specified a sex on their profiles,' Facebook product manager Naomi Gleit said in a company statement.

In English, when users fail to specify what gender they are, Facebook defaults to some form of the gender neutral, plural pronoun 'they'. That option is unavailable when the plural is always masculine or feminine in other languages.

'People who haven't selected what sex they are frequently get defaulted to the wrong sex,' Ms Gleit wrote.

Unless the gender of the user is clear, Facebook does not know which pronoun to use to notify other members add information to the site. This common English problem is multiplied in languages where masculine and feminine distinctions are grammatically ingrained.

The site will now let users specify whether they are male or female on their basic membership profile. It will prompt existing users to define themselves.

Facebook has an opt-out option for members who choose not to specify their gender or do not consider gender to be clear cut. Members can remove mention of gender from messages about their activities.

'We've received pushback in the past from groups that find the male/female distinction too limiting,' Ms Gleit said.

The option is similar to a feature that lets members hide birthdays or the year they were born, a spokesman added. -- REUTERS