A proposal to introduce sharing of assessment base by spouses in the Czech social pension insurance is confronted with the pension theory and policy. The proposed "joint social insurance" should arise automatically, with the option of cancellation based on an agreement. The case has primarily confirmed the need to respect the basic concept of public pensions in the given country. The concept of pensions as entitlements of individuals, and not families, is in conflict with the mentioned proposal which cannot be overcome in the conditions of the complicated defined benefit system. After a potential transition to a notional defined contribution system the sharing of pensions would be feasible - but not necessary. A separate issue is potential dividing of pension entitlements in case of a divorce which can be implemented as a part of dividing the joint assets, regardless of the pension concept. The importance of dividing of pension entitlements is lower in the Czech Republic than in most other countries as a result of a relatively small gender gap in pensions, which is a result of the dominant role of an implicit flat-rate pension in the system. These conclusions are based on a system analysis of foreign experience.