Welsh speakers have been urged by a former mayor of Aberystwyth to have more children to help secure the future of the language.
Mr Jobbins said politicians should not be afraid of the issue
Sion Jobbins, who has recently become a father for the third time, said politicians need to tackle the subject.
Mr Jobbins said passing the language on within families was important "but to what purpose if there are no children?"
The Welsh Language Board said it was already promoting greater day-to-day use of Welsh in the home.
Mr Jobbins, 38, who was a Plaid Cymru candidate in the 2003 assembly elections, was speaking to the BBC's Maniffesto programme.
He called on politicians not be afraid of discussing a subject that has "revolutionary implications in economic and social terms" and a subject that was very relevant to Welsh-speakers.
He said that the lower birth rate was a subject ignored by politicians and language movements, although it had an effect on the future of the language and on the community in general.
"The decline in the birth rate has an effect on the future of the economy, pensions, health, social policies and the Welsh language," he said.
According to statistics Mr Jobbins said that there are fewer children being born to fewer women.
"In Wales and England the birth rate is 1.7 children [per woman] compared to 2.4 back in the 1990s.
"According to experts a community needs 2.2 to regenerate itself."
He said he was not calling on every family to have half a dozen children but wanted policies on sustainable population.
"Many fear that there is overpopulation in the world that effects the environment.
"But the reality in Wales is that fewer children are being born and the population is rising.
"It's not a politician's job to say when and how many children to have but it is a politician's, the media and leaders in Wales' responsibility to look at the future welfare of the state".
'Grasp of Welsh'
He wanted to raise awareness of the issue and said a strategy needed to be developed "that will make it easier to the ones that want to have children to have them."
Mr Jobbins, who works for the National Library of Wales, said the declining birth rate had a direct effect on the Welsh language.
"The Welsh Language Board acknowledges that it is important to pass a language on within the family but to what purpose if there are no children?
"For the future of the language we need to increase the number of children being born in Wales, whatever their background."
Rhodri Llwyd Morgan, of the Welsh Language Board said that projects to urge the use of Welsh at home and money to the Welsh language nursery movement gave "the first opportunity for children to have a grasp of Welsh".
He added: "There is no doubt that this is the main area to promote the language and it is a vital place if Welsh is to survive as a language from day to day.
"Through the Twf project we are promoting the language in the home and that in the long run is the only way any minority language will survive."