The personality of Godhead said: under the supervision of the Supreme Lord and according to the result of his work the living entity, the soul, is made to enter into the womb of a women through the particle of the men semen to assume a particular type of body. Srimad Bhagavatam 3:31:1 The modern science says- It is the man who caused the future child to be male or female due to the variation of X-Y chromosome. The “the particle of the men semen to assume a particular type of body” tell about the variation of child whether to be male or female. “kalalaḿ tv eka-rātreṇa pañca-rātreṇa budbudam daśāhena tu karkandhūḥ peśy aṇḍaḿ vā tataḥ param” Srimad Bhagavatam 3:31:2 On the first night, the sperm and ovum mix, and on the fifth night the mixture ferments into a bubble. On the tenth night it develops into a form like a plum, and after that, it gradually turns into a lump of flesh or an egg, as the case may be. "māsena tu śiro dvābhyāḿ bāhv-ańghry-ādy-ańga-vigrahaḥ nakha-lomāsthi-carmāṇi lińga-cchidrodbhavas tribhiḥ Srimad Bhagavatam 3:31:3 In the course of a month, a head is formed, and at the end of two months the hands, feet and other limbs take shape. By the end of three months, the nails, fingers, toes, body hair, bones and skin appear, as do the organ of generation and the other apertures in the body, namely the eyes, nostrils, ears, mouth and anus. "caturbhir dhātavaḥ sapta pañcabhiḥ kṣut-tṛḍ-udbhavaḥ ṣaḍbhir jarāyuṇā vītaḥ kukṣau bhrāmyati dakṣiṇe Srimad Bhagavatam 3:31:4 Within four months from the date of conception, the seven essential ingredients of the body, namely chyle, blood, flesh, fat, bone, marrow and semen, come into existence. At the end of five months, hunger and thirst make themselves felt, and at the end of six months, the fetus, enclosed by the amnion, begins to move on the right side of the abdomen Srimad Bhagavatam contains the knowledge of how fetus developed and it is proved by the modern science. Not a single mistake can be found thorough out the nine month period, though it is written over thousands of years.