My colleagues are entitled to 1 week of parental leave following the birth or adoption of a child which they are a parent of if they are NOT the primary care-giver of the child. In the case of a same sex couple the parent who is not the primary care-giver is entitled to this week of paid leave. Parental leave comes out of holiday entitlements, if you don't have any holiday leave owing then the parental leave is unpaid. The primary care-giver is entitled to 10 weeks paid leave at full pay (this 'maternity' leave is paid by my employer and is separate to all other entitlements). Only ONE parent can claim to be the primary caregiver and my employer requires a statutory declaration to state that this is the parent claiming paid maternity leave. I work with many same-sex couples, some of whom have become parents. The system of leave entitlements seems to work quite well.

My DH has negotiated the same arrangement from his employer and after the birth of our next child he will take one week of leave, paid from his holiday leave entitlement. He works for a small company, I work for a large organisation. At this point, I believe that 'paternity' leave ('parental' leave at my work!) is very much determined by each individual employer.