the couple concerned give their written consent; and
b.
preservation is intended to permit subsequent establishment of a pregnancy.
2 The preservation period is limited to five years. At the request of the couple concerned, the preservation period shall be extended by a maximum of five years.37
3 Either partner may revoke his or her consent at any time in writing.38
4 If consent is revoked and the preservation period expires, then the impregnated ova and the embryos in vitro shall be be destroyed immediately. The provisions of the Stem Cell Research Act of 19 December 200339 are reserved.40