经曰∶天地，万物之父母也。阴阳，血气之男女也。男子负阴而抱阳，女子负阳而抱阴。南
方，火也，男子南面而生，则两寸在南，而得元阳，故寸脉洪大，而尺脉微弱；女子北面而生，则两
寸在北，而得元阴，故寸脉微弱，而尺脉洪大也。男得女，为不足；女克男，为太过。《脉诀》
云∶女人反此，皆看之尺脉，第三同断病，正此谓也。
盖妇人受孕，犹曳地之道，阴阳和而万物生焉。夫妇之道，阴阳和而男女生焉。妇人经水匀调，
百病不生，然后孕育成矣。夫受胎以血为主，叔和云∶血旺气衰应有体，血衰气旺定无娠。尺微关
滑数流利并雀啄，皆是胎脉见，孕母不知觉。左手带纵，两男子；右手带横，一双女；左手脉逆
生，三男；右手脉顺还，三女；左手太阳浮，大男；右手太阴沉，细女。诸阳为男，诸阴为女。仲
景云∶脉有相承，纵横逆顺。何也？曰∶水行乘火，金行乘木，曰纵；火行乘水，木行乘金，曰逆；
金行乘水，木行乘火，曰顺。或曰∶脉有残贼，何也？弦、紧、浮、滑、沉、涩，此六脉者，贼
也。然诸贼作病，是为残也。且孕脉夫乘妻亏纵气露，妻乘夫亏横气助，子乘母亏逆气恭，母乘子
亏顺气护。夫阴阳二气，若阴血先至，阳精后冲，纵气来乘，如雾露之降升，血裹精，此为夫乘
妻亏纵气雾，则男形成矣；若阳精先至，阴血后恭，两傍横气来助佐，而升精裹血，此谓妻乘夫
亏横气助，则女胎成矣。凡胎气骤聚，必带纵横逆顺，方成胎也。
《黄帝内经》说：天和地，是万物的父母。阴和阳，对应着血与气中的男性与女性特征。男子背负阴而怀抱阳，女子背负阳而怀抱阴。南方属火，男子面向南而生（象征顺应阳气），则两手寸脉位于南方，得到元阳之气，所以寸脉洪大，而尺脉微弱；女子面向北而生（象征顺应阴气），则两手寸脉位于北方，得到元阴之气，所以寸脉微弱，而尺脉洪大。男脉得女脉之象，为不足；女脉克男脉之象，为太过。《脉诀》说：女人的脉象与此相反，都要观察尺脉，在第三指处判断疾病，正是说的这个意思。
大概妇人受孕，就像大地承载万物一样，阴阳调和而万物产生。夫妇之道，也是阴阳调和而男女诞生。妇人月经均匀调畅，百病不生，然后才能孕育成胎。受胎以血为主，王叔和说：血旺气衰应当有孕，血衰气旺必定无娠。尺脉微弱、关脉滑数流利并见雀啄脉，都是胎脉的表现，孕妇自己并不知晓。左手脉象带纵势，预示生两个男孩；右手脉象带横势，预示生一双女孩；左手脉象逆生，生三个男孩；右手脉象顺还，生三个女孩；左手太阳脉浮，生大男孩；右手太阴脉沉细，生小女孩。凡是阳脉主男，阴脉主女。张仲景说：脉象有相承、纵横、逆顺的变化。为什么呢？回答说：水行乘火，金行乘木，称为纵；火行乘水，木行乘金，称为逆；金行乘水，木行乘火，称为顺。有人问：脉象中有残贼脉，是怎么回事呢？弦、紧、浮、滑、沉、涩这六种脉象，就是贼脉。然而各种贼脉引发疾病，这就是“残”的意思。况且妊娠脉象中，夫乘妻亏表现为纵气显露，妻乘夫亏表现为横气相助，子乘母亏表现为逆气恭敬，母乘子亏表现为顺气护卫。如果阴阳二气中，阴血先到，阳精后冲，纵气来乘，如同雾露升降，血包裹精，这叫作“夫乘妻亏纵气雾”，则男胎形成；如果阳精先到，阴血后到，两旁的横气来辅助，升起的精包裹血，这叫作“妻乘夫亏横气助”，则女胎形成。凡胎气骤然聚集，必然带有纵横逆顺的特征，才能形成胎体。
The *Huangdi Neijing* (Yellow Emperor's Inner Canon) states: Heaven and Earth are the parents of all things. Yin and Yang correspond to the male and female aspects of blood and qi. Men carry Yin and embrace Yang, while women carry Yang and embrace Yin. The South belongs to Fire. When men face South at birth (symbolizing adherence to Yang Qi), their Cun (Inch) pulses are located in the South, receiving Yuan Yang (Original Yang), thus the Cun pulse is洪大 (Hongda, large and forceful), while the Chi (Cubit) pulse is weak. Women face North at birth (symbolizing adherence to Yin Qi), their Cun pulses are located in the North, receiving Yuan Yin (Original Yin), thus the Cun pulse is weak, while the Chi pulse is洪大 (Hongda, large and forceful). A man's pulse resembling a woman's indicates deficiency; a woman's pulse overcoming a man's indicates excess. The *Mai Jue* (Pulse Classic) states: "Women's pulses are the reverse of this; one must observe the Chi pulse, and diagnose disease at the third position," which refers precisely to this principle.
Generally, a woman's conception is like the earth bearing things; when Yin and Yang harmonize, all things are born. The way of husband and wife is also that when Yin and Yang harmonize, males and females are born. When a woman's menstruation is regular and smooth, and hundred diseases do not arise, then pregnancy can be formed. Conception is primarily based on blood. Wang Shuhe stated: "When blood is abundant and qi is deficient, there should be pregnancy; when blood is deficient and qi is abundant, there will certainly be no pregnancy." A weak Chi pulse, a slippery and rapid Guan (Bar) pulse with smooth flow, and the appearance of Que Zhuo (Sparrow Pecking) pulse are all signs of fetal pulses, though the pregnant mother may not feel them. If the Left Hand pulse shows a Zong (Longitudinal) pattern, it predicts two boys; if the Right Hand pulse shows a Heng (Transverse) pattern, it predicts twin girls. If the Left Hand pulse is Ni (Reverse), it predicts three boys; if the Right Hand pulse is Shun (Smooth/Return), it predicts three girls. If the Taiyang (Greater Yang) pulse on the Left is Fu (Floating), it predicts an older boy; if the Taiyin (Greater Yin) pulse on the Right is Chen (Deep) and Xi (Fine), it predicts a girl. Generally, Yang pulses indicate males, and Yin pulses indicate females. Zhang Zhongjing stated: "Pulses have characteristics of Xiang Cheng (Mutual Inheritance), Zong Heng (Longitudinal and Transverse), and Ni Shun (Reverse and Smooth)." Why? The answer is: Water overcoming Fire, and Metal overcoming Wood, are called Zong (Longitudinal); Fire overcoming Water, and Wood overcoming Metal, are called Ni (Reverse); Metal overcoming Water, and Wood overcoming Fire, are called Shun (Smooth). One might ask: What are the Can Zei (Residual and Robber) pulses? The six pulses of Xian (Wiry), Jin (Tight), Fu (Floating), Hua (Slippery), Chen (Deep), and Se (Choppy) are the Zei (Robber) pulses. However, when various Zei pulses cause disease, this is referred to as "Can" (Residual/Damage). Furthermore, in pregnancy pulses: "Fu Cheng Qi Kui" (Husband overcomes Wife's deficiency) manifests as Zong Qi appearing; "Qi Cheng Fu Kui" (Wife overcomes Husband's deficiency) manifests as Heng Qi assisting; "Zi Cheng Mu Kui" (Child overcomes Mother's deficiency) manifests as Ni Qi being respectful; "Mu Cheng Zi Kui" (Mother overcomes Child's deficiency) manifests as Shun Qi protecting. If Yin Blood arrives first and Yang Essence rushes later, Zong Qi comes to overcome, similar to the rising and falling of mist and dew, where blood wraps essence; this is called "Fu Cheng Qi Kui Zong Qi Wu" (Husband overcomes Wife's deficiency with Longitudinal Mist Qi), and the male fetus forms. If Yang Essence arrives first and Yin Blood follows respectfully, the Heng Qi from both sides assists, and the rising essence wraps blood; this is called "Qi Cheng Fu Kui Heng Qi Zhu" (Wife overcomes Husband's deficiency with Transverse Assistance Qi), and the female fetus forms. Whenever fetal Qi gathers suddenly, it must possess Zong, Heng, Ni, and Shun characteristics to form a fetus.