▎ 摘　　要

NOVELTY - Determining (M1) the sex of a fetus, comprises: (a) obtaining a biological sample from a subject who is pregnant or suspected of being pregnant comprising fetal nucleic acids; (b) performing isothermal amplification on at least one target fetal nucleic acid in the sample to generate reporter molecules if the target nucleic acids are present in the sample; (c) detecting the reporter molecules, where detection of the reporter molecules indicates the presence of target fetal nucleic acids in the sample; and (d) determining the sex of the fetus based on detecting the presence of the target fetal nucleic acids in the sample. USE - The method is useful for determining the sex of a fetus. ADVANTAGE - The method: determines the sex of the fetus with at least 90% accuracy; and provides rapid detection of fetal nucleic acids in biological sample. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) determining (M2) the sex of a fetus, comprising steps (a)-(c) as per se; (2) determining (M3) the sex of a fetus comprising (a1) obtaining a biological sample from a subject who is pregnant or suspected of being pregnant comprising fetal nucleic acids, (b1) contacting the sample with a clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated protein (Cas) effector protein, a guide RNA, and a labeled reporter DNA molecule, where the labeled reporter DNA molecule is cleaved if one or more target fetal nucleic acids are present in the sample, (c1) detecting a signal produced by the cleavage of the labeled reporter DNA molecule by the CRISPR/Cas effector protein, where detection of the signal indicates the presence of the target fetal nucleic acids in the sample, and (d1) determining the sex of the fetus based on detecting the presence of the target fetal nucleic acids in the sample; (3) determining (M4) the sex of a fetus comprising steps (a1)-(c1) as per se; (4) determining (M5) the sex of a fetus, comprising (a2) obtaining a biological sample from a subject who is pregnant or suspected of being pregnant comprising fetal nucleic acids, (b2) performing isothermal amplification on at least one target fetal nucleic acids in the sample, (c2) contacting the sample with a CRISPR/Cas effector protein, a guide RNA, and a labeled reporter DNA molecule, where the labeled reporter DNA molecule is cleaved if at least one target fetal nucleic acid are present in the sample, (d2) detecting a signal produced by the cleavage of the labeled reporter DNA molecule by the CRISPR/Cas effector protein, where detection of the signal indicates the presence of the target fetal nucleic acids in the sample, and (e2) determining the sex of the fetus based on detecting the presence of the target fetal nucleic acids in the sample; (5) determining (M6) the sex of a fetus, comprising steps (a2)-(d2) as per se; and (6) a device for detecting the presence of at least one target fetal nucleic acids in a biological sample, comprising a lateral flow strip, a detection region on the lateral flow strip comprising a detectable particle or label, and a fluid sample comprising a maternal biological sample comprising fetal nucleic acids, where the detection region provides a visual colorimetric signal indicating the presence of the target fetal nucleic acid in the fluid sample in less than two hours by capillary flow.