Yes, very much so I think, hve tried to list some possible factors below...
The increased acceptaility of alternative social norms such as divorce and remarriage, living together without being married, more common separation and step families and having a number of relationships, same sex couples, abortion, increased sexual activity especially among younger people (flings and one night stands etc... resulting in pregnancy and the soaring teenage pregnancy rate), increased independence especially of women moving away and going on to study and delaying starting a family due to career etc...Social factors such as the benefits system. Increased availability and acceptance of contraception. Availability of IVF treatment and other ferility assistance and increased multiple births, surrogacy. Increased unknown parentage. Possibility of sperm donation.