SB 9.9.31

tasya sādhor apāpasya
 bhrūṇasya brahma-vādinaḥ
kathaṁ vadhaṁ yathā babhror
 manyate san-mato bhavān
Word for word: 
tasya — of him; sādhoḥ — of the great saintly person; apāpasya — of one who has no sinful life; bhrūṇasya — of the embryo; brahma-vādinaḥ — of one who is well versed in Vedic knowledge; katham — how; vadham — the killing; yathā — as; babhroḥ — of a cow; manyate — you are thinking; sat-mataḥ — well recognized by higher circles; bhavān — your good self.
Translation: 
You are well known and worshiped in learned circles. How dare you kill this brāhmaṇa, who is a saintly, sinless person, well versed in Vedic knowledge? Killing him would be like destroying the embryo within the womb or killing a cow.
Purport: 

As stated in the Amara-kośa dictionary, bhrūṇo ’rbhake bāla-garbhe: the word bhrūṇa refers either to the cow or to the living entity in embryo. According to Vedic culture, destroying the undeveloped embryo of the soul in the womb is as sinful as killing a cow or a brāhmaṇa. In the embryo, the living entity is present in an undeveloped stage. The modern scientific theory that life is a combination of chemicals is nonsense; scientists cannot manufacture living beings, even like those born from eggs. The idea that scientists can develop a chemical situation resembling that of an egg and bring life from it is nonsensical. Their theory that a chemical combination can have life may be accepted, but these rascals cannot create such a combination. This verse refers to bhrūṇasya vadham — the killing of a bhrūṇa or destruction of the embryo. Here is a challenge from the Vedic literature. The crude, atheistic understanding that the living entity is a combination of matter belongs to the grossest ignorance.