The doctrine is sex-neutral in origin: it was built in Hokkanen v. Finland, no. 19823/92, 23 September 1994 (father applicant; violation of Article 8 for non-enforcement of his access rights from 10 May 1990 to 21 October 1993; no violation as to custody; HUDOC item 001-57911) and Ignaccolo-Zenide v. Romania, no. 31679/96, 25 January 2000 (mother applicant; violation of Article 8 for failure to enforce her return and contact rights; HUDOC item 001-58448). Kuppinger v. Germany, no. 62198/11, 15 January 2015, paras 101-103 restates the test, including that sanctions must not be ruled out in the event of unlawful behaviour by the parent with whom the child lives; the Court there found an Article 8 violation in the proceedings to enforce an interim contact decision, plus a violation of Article 13. This lets the page state the enforcement failure without any bias claim: the Court finds violations against states for slow and ineffective enforcement machinery, whoever the parent is, while stressing that the obligation is not absolute and that coercion is limited by the interests of all concerned. Use the full quote from Kuppinger para 102: "the adequacy of a measure is to be judged by the swiftness of its implementation, as the passage of time can have irremediable consequences for relations between the child and the parent who do not cohabit" (or close a shortened version with an ellipsis).
“the adequacy of a measure is to be judged by the swiftness of its implementation, as the passage of time can have irremediable consequences for relations between the child and the parent”