delivered the opinion of the court:
This is an appeal, consolidated in the appellate court, from the entry of two orders by the circuit court of Cook County denying defendants’ motions to strike and dismiss and directing writs of mandamus to issue against defendants (Health & Hospitals Governing Commission of Elinois; James Bailey, Director of Personnel for Cook County Hospitals; and the Merit System Advisory Committee). The orders directed defendants to reinstate relators, John P. Casey, John McIntyre, and William Bamrick, to their former positions of employment at two hospitals which are under the administration of the Health & Hospitals Governing Commission of Illinois (Commission), an independent county agency created by the legislature to operate certain medical institutions (Ill. Rev. Stat. 1971, ch. 34, par. 5011 et seq.). Defendants were further commanded to pay relators the salaries appropriate for their positions from the dates of their termination to the date of their reinstatement. The appellate court affirmed the orders of the circuit court (37 Ill. App. 3d 1056), and we granted leave to appeal.
Relators Casey and McIntyre were employed as firemen-oilers at Oak Forest Hospital. Each had attained the status of career employee pursuant to the Commission’s statutorily required merit system. Under the provisions of the statute governing the Commission, it is provided that “[n]o merit or career employee may be discharged, demoted or suspended for a period of more than 30 days, except for cause and upon written charges.” (Ill. Rev. Stat. 1971, ch. 34, par. 5026.) Despite the foregoing provision, the Commission adopted a resolution establishing mandatory retirement for institutional em*112ployees, effective January 1, 1973. Pursuant to this policy, Casey and McIntyre were summarily retired by defendants on December 29 and December 31, 1972, respectively, without cause or the presentation of written charges and without a hearing.
The petition of relators Casey and McIntyre represented that other institutional employees who had been discharged pursuant to defendants’ compulsory-retirement program had brought actions against the Commission in the circuit court of Cook County. Relators’ petition also stated that consolidated appeals had been taken in those cases from orders declaring the mandatory-retirement invalid and directing the reinstatement of those other employees. The petition further noted that on August 15, 1974, in the case of Sibley v. Health & Hospitals’ Governing Com. (1974), 22 Ill. App. 3d 632, the appellate court affirmed the orders of the circuit court, holding that the Commission had no inherent power to remove merit system employees for age. On November 6, 1974, Casey and McIntyre served notice and demand upon defendants to restore relators to their former positions.
Relator Bamrick served as a fireman’s helper at Cook County Hospital from 1954 until December 31, 1972, at which time he was summarily discharged by defendants pursuant to their compulsory-retirement program. The complaint asserts that, in light of the appellate court’s decision in Sibley v. Health & Hospitals Governing Com. (1974), 22 Ill. App. 3d 632, the rule which compelled Bamrick to retire is null and void and that reinstatement is thus appropriate.
On November 26, 1974, relators Casey and McIntyre and relator Bamrick filed their respective mandamus actions praying for reinstatement and payment of back salary. Defendants responded to both complaints with motions to strike and dismiss “for the reason that *113plaintiffs’ suit is not timely brought.” The trial court denied these motions and, after defendants chose to stand on their motions and not provide answers, writs of mandamus were issued as prayed. The appellate court affirmed. 37 Ill. App. 3d 1056.
The only issue raised on appeal is whether relators’ right to reinstatement by way of mandamus is barred by laches as a result of their 23-month delay in bringing their actions.
We agree with defendants’ initial assertion that where an unreasonable delay is apparent on the face of a complaint, the plaintiff has an affirmative duty to set forth a valid excuse therefor, or the action may be barred by laches. (Schultheis v. City of Chicago (1909), 240 Ill. 167, 170; Haas v. Commissioners of Lincoln Park (1930), 339 Ill. 491, 503.) However, according to section 43(4) of the Civil Practice Act (Ill. Rev. Stat. 1973, ch. 110, par. 43(4)), affirmative defenses, such as laches, “must be plainly set forth in the answer or reply.” By standing on their motions to strike, defendants waived their answers and thereby failed to raise the defense of laches under section 43(4).
Admittedly, section 43(4) has not been construed to mean that affirmative defenses may be raised only by answer or reply. Where laches is apparent on the face of a complaint and plaintiff has allegedly failed to set forth a reasonable excuse for the delay, “there appears to be no reason why the defect cannot be raised by motion so long as the motion specifically points out the defect complained of.” (Emphasis added.) (Holland v. Richards (1955), 4 Ill. 2d 570, 573.) Accordingly, under section 45(1) of the Civil Practice Act (Ill. Rev. Stat. 1973, ch. 110, par. 45(1)), a party may, by motion, object to pleadings; but it is incumbent upon the moving party to “point out specifically the defects complained of” in order to give plaintiffs the opportunity to file amended com*114plaints to correct any deficiencies.
On oral argument, counsel for the defense made it clear that defendants’ motions to strike and dismiss had been brought under section 45 of the Civil Practice Act and contended that relators’ complaints are defective for allegedly failing to set forth any reasonable excuse for the 23-month delay in bringing this action. However, by stating simply that “plaintiffs’ suit is not timely brought,” defendants’ motions failed to specifically point out the alleged defect in relators’ complaints and thereby failed to raise the defense of laches under section 45.
Although defendants’ cause must fail on the issue of defective pleadings alone, for additional reasons the defendants’ position cannot be sustained.
Defendants contend that the complaints of relators failed to affirmatively set forth any facts excusing the 23-month delay in bringing this action and that relators are thus guilty of laches. This argument is without merit. The mere passage of time does not bar relief where a reasonable excuse for the delay is apparent in the complaint. (Nelson v. Wilson (1928), 331 Ill. 11, 15; see also Duncan v. Dazey (1925), 318 Ill. 500, 525.) First, a delay of 23 months by discharged employees in bringing mandamus actions for reinstatement and accrued back pay, which is caused by awaiting the disposition of a prior pilot suit involving employees discharged under the same policy, is reasonable and does not constitute laches. (Duncan v. Summerfield (D.C. Cir. 1957), 251 F.2d 896, 897; Jones v. Summerfield (D.C. Cir. 1959), 265 F.2d 124, 125; State ex rel. Prior v. Kansas City (Mo. 1924), 261 S.W. 112, 114.) Second, the record discloses that relators filed their mandamus actions on November 26, 1974, little more than three months after the appellate court rendered its decision in Sibley v. Health & Hospitals Governing Com. (1974), 22 Ill. App. 3d 632. From the facts alleged in the complaints, which included a history of the Sibley litigation, it is a reasonable *115and logical inference that all relators at bar were awaiting the outcome of the prior, controlling litigation. Therefore, the mandamus complaints sufficiently demonstrated why there had not been an earlier institution of the action.
In addition, defendants fail to recognize that laches is not simply a matter of time; rather, it is a principle of “inequity founded upon some change in the condition or relation of the property and the parties” (Holland v. Richards (1955), 4 Ill. 2d 570, 578). That is, it must appear that a plaintiff’s unreasonable delay in asserting his rights has prejudiced and misled the defendant, or caused him to pursue a course different from what he would have otherwise taken. (People ex rel. Griffin v. City of Chicago (1943), 382 Ill. 500, 504; People ex rel. Gramlich v. City of Peoria (1940), 374 Ill. 313, 322; see also Haas v. Commissioners of Lincoln Park (1930), 339 Ill. 491, 502; Neidhardt v. Frank (1927), 325 Ill. 596, 601.) If the defendant is not injured by the delay, then plaintiff is not guilty of laches.
The defendants contend that prejudice to an employer is inherent any time a public employee delays in seeking reinstatement because another person must be hired to replace the discharged employee. That is, if the employee succeeds in securing accrued back pay, the employer must pay him for services rendered by a third person and for which that third person has already been compensated. Thus, the longer the delay, the greater the burden on the employer. We recognize this risk and agree that the defense of laches should be available to an employer when sued by a discharged public employee.
In this case, however, the discharge of relators was not an isolated incident. Relators were discharged in furtherance of a general policy involving numerous employees, at least eight of whom were already involved in actions, which had been consolidated into the Sibley appeal against the Commission. It is thus apparent that the defendants *116had no intention of reinstating any employee who was discharged pursuant to their mandatory-retirement program unless and until such program was ruled invalid by the appellate court in Sibley. Moreover, immediate action by relators would have been futile since the defendants undoubtedly would have sought and received a delay pending the outcome in Sibley. Therefore, if relators recover accrued back pay for services rendered by another person, the Commission will be injured by its own wrongful retirement policy, but not by relators’ awaiting the outcome of prior litigation (before taking these actions). See Duncan v. Summerfield (D.C. Cir. 1957), 251 F.2d 896, 897.
Since all parties understood that Sibley was a test case which directly controlled relators’ claims and that relators intended to await the outcome of that litigation before bringing their actions, it was incumbent upon the Commission to come forward and demonstrate that relators’ delay had otherwise prejudiced it of induced it to change its position. Under the circumstances, we believe that the Commission failed to do so.
Hence, we affirm the judgment of the appellate court.
Judgment affirmed.