What is the test for a motion to dismiss a claim for violation of a constitutional right to familial association?

Plaintiffs bring their only federal claim for violation of their constitutional right to familial association under 42 U.S.C. 1983 against the individual defendants. (Compl. at 60.) Defendants move to dismiss the complaint, arguing that plaintiffs have not alleged facts that state a claim upon which relief could be granted. (Doc. No. 16-1 at 4.) "To succeed on a 1983 claim, a plaintiff must show that (1) the conduct complained of was committed by a person acting under color of state law; and (2) the conduct deprived the plaintiff of a federal constitutional or statutory right." Tatum v. City & County of San Francisco, 441 F.3d 1090, 1094 (9th Cir. 2006). Here, plaintiffs allege that the individual defendants were acting under color of state law. (Compl. at 8.) The sole issue posed by the pending motion to dismiss this cause of action is whether plaintiffs have adequately alleged that the conduct of the individual defendants deprived plaintiffs of a constitutional right.