A guide has been published to help workers and employers understand new rights on sharing maternity or adoption leave.
The conciliation service Acas said that couples finding out now they are expecting a child will be among the first parents eligible for the new rights, which come into force next April.
An estimated 285,000 working couples will be eligible to share their leave under moves to make the system more flexible.
Understanding the new rules
Stewart Gee of Acas said: "Our guide was produced with input from large and small employers, family groups and trade unions and is designed to ensure working parents and employers alike can understand the new shared parental leave arrangements.
"We advise employers and employees to start early with discussions to ensure that they can agree the sort of arrangements which work best for business and working families. We are also running training courses to help employers prepare for the legal changes."
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Employment relations minister Jo Swinson said: "Dads have a key role to play in the early weeks and months of a baby's life and it is right that the arrangements for parental leave should reflect that.
"Shared parental leave is not only good news for parents-to-be, but for employers who will benefit from having a workforce that is more flexible and motivated."
Under the new system, a pregnant woman will continue to have access to 52 weeks of maternity leave and 39 weeks of pay but from April, working families will have the opportunity to share this leave.
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